Article Directory
Chapter One
1.3
#include<iostream>
using namespace std;
int main()
{
cout << "hello world" << endl;
system("pause");
return 0;
}
1.4
#include<iostream>
using namespace std;
int main()
{
int v1 = 0;
int v2 = 0;
cin >> v1 >> v2;
cout << v1 << "与" << v2 <<"积为：" << v1*v2 << endl;
system("pause");
return 0;
}
1.6
Illegal title
1.8
#include<iostream>
using namespace std;
int main()
{
cout << "/*";
cout << "*/";
//cout <</*"*/"*/;错误会认为是不完整字符，在封号前加“就对了
cout <</*"*/"/*"/*”*/;
system("pause");
return 0;
}
1.9
#include<iostream>
using namespace std;
int main()
{
int sum = 0;
int v = 50;
while (v <= 100)
{
sum += v;
++v;
}
cout << "50到100和为：" << sum << endl;
system("pause");
return 0;
}
1.10
#include<iostream>
using namespace std;
int main()
{
int v = 10;
cout << "10-0之间的整数为：" << endl;
while (v >= 0)
{
cout << v<<" ";
v--;
}
cout << endl;
system("pause");
return 0;
}
1.11
#include<iostream>
using namespace std;
int main()
{
int v1 = 0;
int v2 = 0;
cout << "请输入两个数" << endl;
cin >> v1 >> v2;
cout << "这两个数之间整数为:" << endl;
if (v1 > v2)
{
while (v1 >= v2)
{
cout << v2 << " ";
v2++;
}
}
else
{
while (v2 >= v1)
{
cout << v1 << " ";
v1++;
}
}
cout << endl;
system("pause");
return 0;
}
1.12
-100 to 100 integer addition sum=0
1.13
#include<iostream>
using namespace std;
void test1()
{
int sum = 0;
for (int i = 50; i <= 100; i++)
{
sum += i;
}
cout << "test1 sum= " << sum << endl;
}
void test2()
{
cout << "test2 ";
for (int i = 10; i >= 0; i--)
{
cout << i << " ";
}
cout << endl;
}
void test3()
{
int v1 = 0;
int v2 = 0;
cout << "请输入两个数" << endl;
cin >> v1 >> v2;
cout << "这两个数之间整数为:" << endl;
if (v1 > v2)
{
for (int i = v2; i <= v1; i++)
{
cout << i << " ";
}
}
else
{
for (int i = v1; i <= v2; i++)
{
cout << i << " ";
}
}
cout << endl;
}
int main()
{
test1();
test2();
test3();
system("pause");
return 0;
}
1.16
#include<iostream>
using namespace std;
int main()
{
int sum = 0, value = 0;
cout << "输入一组数 ，按ctrl+z结束" << endl;
/*while (cin >> value)
sum += value;
cout << sum << endl;*/
for (; cin >> value;)
{
sum += value;
}
cout << sum << endl;
system("pause");
return 0;
}
1.18
#include<iostream>
using namespace std;
int main()
{
int currval = 0;
int val = 0;
int count = 1;
if (cin >> currval)
{
while (cin >> val)
{
if (currval == val)
{
count++;
}
else
{
cout << currval << " 出现了 " << count << " 次" << endl;
count = 1;
currval = val;
}
}
cout << currval << " 出现了 " << count << " 次" << endl;
}
system("pause");
return 0;
}
1.19
#include<iostream>
using namespace std;
int main()
{
int v1 = 0;
int v2 = 0;
cout << "请输入两个数" << endl;
cin >> v1 >> v2;
if (v1 < v2)
{
for (int i = v2; i >= v1; i--)
{
cout << i << " ";
}
}
else
{
for (int i = v1; i >= v2; i--)
{
cout << i << " ";
}
}
cout << endl;
system("pause");
return 0;
}
1.20
#pragma once
#ifndef SALESITEM_H
// we're here only if SALESITEM_H has not yet been defined
#define SALESITEM_H
//#include "Version_test.h"
// Definition of Sales_item class and related functions goes here
#include <iostream>
#include <string>
class Sales_item {
// these declarations are explained section 7.2.1, p. 270
// and in chapter 14, pages 557, 558, 561
friend std::istream& operator>>(std::istream&, Sales_item&);
friend std::ostream& operator<<(std::ostream&, const Sales_item&);
friend bool operator<(const Sales_item&, const Sales_item&);
friend bool
operator==(const Sales_item&, const Sales_item&);
public:
// constructors are explained in section 7.1.4, pages 262 - 265
// default constructor needed to initialize members of built-in type
#if defined(IN_CLASS_INITS) && defined(DEFAULT_FCNS)
Sales_item() = default;
#else
Sales_item() : units_sold(0), revenue(0.0) {
}
#endif
Sales_item(const std::string& book) :
bookNo(book), units_sold(0), revenue(0.0) {
}
Sales_item(std::istream& is) {
is >> *this; }
public:
// operations on Sales_item objects
// member binary operator: left-hand operand bound to implicit this pointer
Sales_item& operator+=(const Sales_item&);
// operations on Sales_item objects
std::string isbn() const {
return bookNo; }
double avg_price() const;
// private members as before
private:
std::string bookNo; // implicitly initialized to the empty string
#ifdef IN_CLASS_INITS
unsigned units_sold = 0; // explicitly initialized
double revenue = 0.0;
#else
unsigned units_sold;
double revenue;
#endif
};
// used in chapter 10
inlinen bool compareIsbn(const Sales_item& lhs, const Sales_item& rhs)
{
return lhs.isbn() == rhs.isbn();
}
// nonmember binary operator: must declare a parameter for each operand
Sales_item operator+(const Sales_item&, const Sales_item&);
inline bool
operator==(const Sales_item& lhs, const Sales_item& rhs)
{
// must be made a friend of Sales_item
return lhs.units_sold == rhs.units_sold &&
lhs.revenue == rhs.revenue &&
lhs.isbn() == rhs.isbn();
}
inline bool
operator!=(const Sales_item& lhs, const Sales_item& rhs)
{
return !(lhs == rhs); // != defined in terms of operator==
}
// assumes that both objects refer to the same ISBN
Sales_item& Sales_item::operator+=(const Sales_item& rhs)
{
units_sold += rhs.units_sold;
revenue += rhs.revenue;
return *this;
}
// assumes that both objects refer to the same ISBN
Sales_item
operator+(const Sales_item& lhs, const Sales_item& rhs)
{
Sales_item ret(lhs); // copy (|lhs|) into a local object that we'll return
ret += rhs; // add in the contents of (|rhs|)
return ret; // return (|ret|) by value
}
std::istream&
operator>>(std::istream& in, Sales_item& s)
{
double price;
in >> s.bookNo >> s.units_sold >> price;
// check that the inputs succeeded
if (in)
s.revenue = s.units_sold * price;
else
s = Sales_item(); // input failed: reset object to default state
return in;
}
std::ostream&
operator<<(std::ostream& out, const Sales_item& s)
{
out << s.isbn() << " " << s.units_sold << " "
<< s.revenue << " " << s.avg_price();
return out;
}
double Sales_item::avg_price() const
{
if (units_sold)
return revenue / units_sold;
else
return 0;
}
#endif
#include<iostream>
using namespace std;
#include"Sales_item.h"
int main()
{
Sales_item book;
cout << "请输入销售记录" << endl;
while (cin >> book)
{
cout << "isbn ,本数，销售额，平均售价" << book << endl;
}
system("pause");
return 0;
}
1.21
#include<iostream>
using namespace std;
#include"Sales_item.h"
int main()
{
Sales_item book1;
Sales_item book2;
Sales_item book3;
cout << "请输入销售记录" << endl;
cin >> book1 >> book2;
if(compareIsbn(book1,book2))
{
book3 = book1 + book2;
cout << "isbn ,本数，销售额，平均售价" << book3 << endl;
}
else
{
cout<<"isbn不同"<<endl;
}
system("pause");
return 0;
}
1.22
#include<iostream>
using namespace std;
#include"Sales_item.h"
int main()
{
Sales_item allbook;
Sales_item book;
cout << "请输入" << endl;
if (cin >> allbook)
{
while (cin >> book)
{
if (compareIsbn(allbook, book))
{
allbook += book;
}
else
{
cout << "isbn不同" << endl;
return -1;
}
}
cout << "isbn 本数 销售额 平均售价" << allbook << endl;
}
else
{
cout << "没有数据" << endl;
return -1;
}
system("pause");
return 0;
}
1.23
#include<iostream>
using namespace std;
#include"Sales_item.h"
int main()
{
Sales_item book1;
Sales_item book2;
int num = 1;
cout << "请输入" << endl;
if (cin >> book1)
{
while (cin >> book2)
{
if (compareIsbn(book1, book2))
{
++num;
}
else
{
cout << "isbn为" << book1.isbn() <<"数量为" << num << endl;
num = 1;
book1 = book2;
}
}
cout << "isbn为" << book1.isbn() << "数量为" << num << endl;
}
else
{
cout << "没有数据" << endl;
return -1;
}
system("pause");
return 0;
}
1.25
#include<iostream>
using namespace std;
#include"Sales_item.h"
int main()
{
Sales_item total;
Sales_item trams;
cout << "请输入:" << endl;
if (cin >> total)
{
while (cin >> trams)
{
if (compareIsbn(total, trams))
{
total += trams;
}
else
{
cout << "isbn 本数 销售额 平均售价" << total << endl;
total = trams;
}
}
cout << "isbn 本数 销售额 平均售价" << total << endl;
}
else
{
cout << "没有数据" << endl;
return -1;
}
system("pause");
return 0;
}
Chapter two
2.2
double
2.3
#include<iostream>
using namespace std;
int main()
{
unsigned u = 10, u2 = 42;
cout << u2 - u << endl;
cout << u - u2 << endl;
int i = 10, i2 = 42;
cout << i2 - i << endl;
cout << i - i2 << endl;
cout << i - u << endl;
cout << u - i << endl;
system("pause");
return 0;
}
2.8
#include<iostream>
using namespace std;
int main()
{
cout << "2\x4d\n";
cout << "2\tM\n";
system("pause");
return 0;
}
2.18
#include<iostream>
using namespace std;
int main()
{
int i = 5, j = 10;
int* p = &i;
cout << p << " " << *p << endl;
p = &j;
cout << p << " " << *p << endl;
j = 30;
cout << p << " " << *p << endl;
system("pause");
return 0;
}
2.34
#include<iostream>
using namespace std;
int main()
{
int i = 0, & r = i;
auto a = r;
const int ci = i, & cr = ci;
auto b = ci;
auto c = cr;
auto d = &i;
auto e = &ci;
auto& g = ci;
cout << a << " " << b << " " << c << " " << d << " " << e << " " << g << endl;
a = 42;
b = 42;
c = 42;
//d = 42;
//e = 42;
//g = 42;
cout << a << " " << b << " " << c << " " << d << " " << e << " " << g << endl;
system("pause");
return 0;
}
2.35
#include<iostream>
#include<typeinfo>
using namespace std;
int main()
{
const int i = 42;
auto j = i;
const auto& k = i;
auto* p = &i;
const auto j2 = i, & k2 = i;
cout << typeid(i).name() << endl;
cout << typeid(j).name() << endl;
cout << typeid(k).name() << endl;
cout << typeid(p).name() << endl;
cout << typeid(j2).name() << endl;
cout << typeid(k2).name() << endl;
system("pause");
return 0;
}
2.38
struct Sales_data
{
string bookno;
int units_sold = 0;
double sellingprice = 0;
double saleprice = 0;
};
2.41
#include<iostream>
using namespace std;
#include<string>
class Sales_data
{
friend istream& operator>>(std::istream&, Sales_data&);
friend ostream& operator<<(std::ostream&, const Sales_data&);
friend bool operator<(const Sales_data&, const Sales_data&);
friend bool operator==(const Sales_data&, const Sales_data&);
public:
Sales_data() = default;
Sales_data(const std::string& book) : bookNo(book), units_sold(0), sellingprice (0.0), saleprice (0.0), discount (0.0) {
}
Sales_data(std::istream& is)
{
is >> *this;
}
public:
Sales_data& operator+=(const Sales_data&);
string isbn() const
{
return bookNo;
}
private:
string bookNo;
int units_sold = 0;
double sellingprice = 0.0;
double saleprice = 0.0;
double discount = 0.0;
};
inline bool compareIsbn(const Sales_data& lhs, const Sales_data& rhs)
{
return lhs.isbn() == rhs.isbn();
}
inline bool operator==(const Sales_data& lhs, const Sales_data& rhs)
{
return lhs.units_sold == rhs.units_sold &&
lhs.sellingprice == rhs.sellingprice &&
lhs.saleprice==rhs.saleprice &&
lhs.isbn() == rhs.isbn();
}
inline bool operator!=(const Sales_data& lhs, const Sales_data& rhs)
{
return !(lhs == rhs);
}
Sales_data& Sales_data::operator+=(const Sales_data& rhs)
{
units_sold += rhs.units_sold;
saleprice = (rhs.saleprice * units_sold + saleprice * units_sold) / (rhs.units_sold + units_sold);
sellingprice = (rhs.sellingprice * units_sold + sellingprice * units_sold) / (rhs.units_sold + units_sold);
if (sellingprice != 0)
{
discount = saleprice / sellingprice;
}
return *this;
}
Sales_data operator+(const Sales_data& lhs, const Sales_data& rhs)
{
Sales_data ret(lhs);
ret += rhs;
return ret;
}
istream& operator>>(std::istream& in, Sales_data& s)
{
double price;
in >> s.bookNo >> s.units_sold >> s.sellingprice >> s.saleprice;
if (in && s.sellingprice != 0)
s.discount = s.saleprice / s.sellingprice;
else
s = Sales_data(); // input failed: reset object to default state
return in;
}
ostream& operator<<(std::ostream& out, const Sales_data& s)
{
out << s.isbn() << " " << s.units_sold << " " << s.sellingprice << " " << s.saleprice << " " <<s.discount;
return out;
}
int main()
{
//1
Sales_data book;
cout << "请输入销售记录" << endl;
while (cin>>book)
{
cout << "isbn 本数 原价 实价 折扣" << book << endl;
}
//2
Sales_data book1;
Sales_data book2;
Sales_data book3;
cout << "请输入两条记录" << endl;
cin >> book1;
cin >> book2;
if (compareIsbn(book1,book2))
{
book3 = book1 + book2;
cout << "isbn 本数 原价 实价 折扣" << book3 << endl;
}
else
{
cout << "isbn不相同" << endl;
}
//3
Sales_data book4;
Sales_data total;
cout << "请输入多条记录" << endl;
if (cin >> total)
{
while (cin >> book4)
{
if (compareIsbn(total, book4))
{
total += book4;
}
else
{
cout << "isbn不相同" << endl;
return -1;
}
}
cout << "isbn 本数 原价 实价 折扣" << total << endl;
}
else
{
cout << "无数据" << endl;
return -1;
}
//4.
Sales_data book5;
Sales_data book6;
int sum = 1;
cout << "请输入多条记录" << endl;
if (cin >> book5)
{
while (cin >> book6)
{
if (compareIsbn(book5, book6))
{
sum++;
}
else
{
cout << "isbn为: " << book5.isbn() << "数量为：" << sum << endl;
sum = 1;
book5 = book6;
}
}
cout << "isbn为: " << book5.isbn() << "数量为：" << sum << endl;
}
else
{
cout << "无数据" << endl;
return -1;
}
system("pause");
return 0;
}
2.42
.h
//#pragma once 第二种方法代替ifndef
#ifndef SALES_DATA_H
#define SALES_DATA_H
#include<iostream>
#include<string>
class Sales_data
{
friend istream& operator>>(std::istream&, Sales_data&);
friend ostream& operator<<(std::ostream&, const Sales_data&);
friend bool operator<(const Sales_data&, const Sales_data&);
friend bool operator==(const Sales_data&, const Sales_data&);
public:
Sales_data() = default;
Sales_data(const std::string& book) : bookNo(book), units_sold(0), sellingprice(0.0), saleprice(0.0), discount(0.0) {
}
Sales_data(std::istream& is)
{
is >> *this;
}
public:
Sales_data& operator+=(const Sales_data&);
string isbn() const
{
return bookNo;
}
private:
string bookNo;
int units_sold = 0;
double sellingprice = 0.0;
double saleprice = 0.0;
double discount = 0.0;
};
inline bool compareIsbn(const Sales_data& lhs, const Sales_data& rhs)
{
return lhs.isbn() == rhs.isbn();
}
inline bool operator==(const Sales_data& lhs, const Sales_data& rhs)
{
return lhs.units_sold == rhs.units_sold &&
lhs.sellingprice == rhs.sellingprice &&
lhs.saleprice == rhs.saleprice &&
lhs.isbn() == rhs.isbn();
}
inline bool operator!=(const Sales_data& lhs, const Sales_data& rhs)
{
return !(lhs == rhs);
}
Sales_data& Sales_data::operator+=(const Sales_data& rhs)
{
units_sold += rhs.units_sold;
saleprice = (rhs.saleprice * rhs.units_sold + saleprice * units_sold) / (rhs.units_sold + units_sold);
sellingprice = (rhs.sellingprice * rhs.units_sold + sellingprice * units_sold) / (rhs.units_sold + units_sold);
if (sellingprice != 0)
{
discount = saleprice / sellingprice;
}
return *this;
}
Sales_data operator+(const Sales_data& lhs, const Sales_data& rhs)
{
Sales_data ret(lhs);
ret += rhs;
return ret;
}
istream& operator>>(std::istream& in, Sales_data& s)
{
double price;
in >> s.bookNo >> s.units_sold >> s.sellingprice >> s.saleprice;
if (in && s.sellingprice != 0)
s.discount = s.saleprice / s.sellingprice;
else
s = Sales_data(); // input failed: reset object to default state
return in;
}
ostream& operator<<(std::ostream& out, const Sales_data& s)
{
out << s.isbn() << " " << s.units_sold << " " << s.sellingprice << " " << s.saleprice << " " << s.discount;
return out;
}
#endif // !SALES_DATA_H
.cpp
#include<iostream>
using namespace std;
#include"Sales_item.h"
int main()
{
Sales_item total;
Sales_item trams;
cout << "请输入:" << endl;
if (cin >> total)
{
while (cin >> trams)
{
if (compareIsbn(total, trams))
{
total += trams;
}
else
{
cout << "isbn 本数 销售额 平均售价" << total << endl;
total = trams;
}
}
cout << "isbn 本数 销售额 平均售价" << total << endl;
}
else
{
cout << "没有数据" << endl;
return -1;
}
system("pause");
return 0;
}
third chapter
3.2
#include<iostream>
using namespace std;
#include<string>
int main()
{
string line;
while (getline(cin, line))
{
cout << line << endl;
}
system("pause");
return 0;
}
#include<iostream>
using namespace std;
#include<string>
int main()
{
string line;
while (cin>>line)
{
cout << line << endl;
}
system("pause");
return 0;
}
3.4
#include<iostream>
using namespace std;
#include<string>
int main()
{
string s1;
string s2;
cin >> s1;
cin >> s2;
if (s1 == s2)
{
cout << "相等" << endl;
}
else if (s1 < s2)
{
cout << "s1<s2" << endl;
cout << s2 << endl;
}
else
{
cout << "s1>s2" << endl;
cout << s1 << endl;
}
system("pause");
return 0;
}
#include<iostream>
using namespace std;
#include<string>
int main()
{
string s1;
string s2;
cin >> s1;
cin >> s2;
auto len1 = s1.size();
auto len2 = s2.size();
if (len1 == len2)
{
cout << "相等" << endl;
}
else if (len1 < len2)
{
cout << "s1比s2短" << endl;
cout << s2 << endl;
}
else
{
cout << "s1比s2长" << endl;
cout << s1 << endl;
}
system("pause");
return 0;
}
3.5
#include<iostream>
using namespace std;
#include<string>
int main()
{
string s1;
string s2;
string s3;
while (cin >> s1)
{
s2 += s1;
cout<<"继续y，停止n"<<endl;
cin>>s3;
if(s3=="y")
{
cout<<"输入下一串字符串"<<endl;
}
else
{
break;
}
}
cout << s2 << endl;
system("pause");
return 0;
}
#include<iostream>
using namespace std;
#include<string>
int main()
{
string s1;
string s2;
string s3;
while (cin >> s1)
{
if (!s2.size())
{
s2 += s1;
}
else
{
s2 += s1;
s2 += " ";
cout << "继续y，停止n" << endl;
cin >> s3;
if (s3 == "y")
{
cout << "输入下一串字符串" << endl;
}
else
{
break;
}
}
}
cout << s2 << endl;
system("pause");
return 0;
}
3.6
#include<iostream>
using namespace std;
#include<string>
int main()
{
string s1;
getline(cin, s1);
for (auto &c : s1)
{
c = 'X';
}
cout << s1 << endl;
system("pause");
return 0;
}
3.7
auto will be automatically recognized as char
3.8
#include<iostream>
using namespace std;
#include<string>
int main()
{
string s1;
getline(cin, s1);
decltype(s1.size()) i = 0;
while (i != s1.size())
{
s1[i] = 'X';
i++;
}
cout << s1 << endl;
system("pause");
return 0;
}
#include<iostream>
using namespace std;
#include<string>
int main()
{
string s1;
getline(cin, s1);
decltype(s1.size()) i = 0;
for(;i<s1.size();i++)
{
s1[i] = 'X';
}
cout << s1 << endl;
system("pause");
return 0;
}
3.10
#include<iostream>
using namespace std;
#include<string>
#include<cctype>
int main()
{
string s1;
getline(cin, s1);
decltype(s1.size()) i = 0;
for(;i<s1.size();i++)
{
if (ispunct(s1[i]))
{
for (decltype(s1.size()) j = i; j < s1.size(); j++)
{
s1[j] = s1[j + 1];
}
}
}
cout << s1 << endl;
system("pause");
return 0;
}
You can see the answer is more concise
3.14
#include<iostream>
using namespace std;
#include<vector>
#include<string>
int main()
{
vector<int> v;
int i = 0;
string cont = "y";
cout << "请输入整数" << endl;
while (cin >> i)
{
v.push_back(i);
cout << "继续添加y 停止n" << endl;
cin >> cont;
if (cont != "y")
{
break;
}
}
for (auto c : v)
{
cout << c << " ";
}
cout << endl;
system("pause");
return 0;
}
3.15
#include<iostream>
using namespace std;
#include<vector>
#include<string>
int main()
{
vector<string> v;
string i = "";
string cont = "y";
cout << "请输入字符串" << endl;
while (cin >> i)
{
v.push_back(i);
cout << "继续添加y 停止n" << endl;
cin >> cont;
if (cont != "y")
{
break;
}
}
for (auto c : v)
{
cout << c << " ";
}
cout << endl;
system("pause");
return 0;
}
3.16
#include<iostream>
using namespace std;
#include<vector>
#include<string>
int main()
{
vector<int>v1;
cout << "v1.size" << v1.size() << endl;
if(v1.size()>0)
{
for (auto c : v1)
{
cout << c << " ";
}
cout << endl;
}
vector<int>v2(10);
cout << "v2.size" << v2.size() << endl;
if(v2.size()>0)
{
for (auto c : v2)
{
cout << c << " ";
}
cout << endl;
}
vector<int>v3(10, 42);
cout << "v3.size" << v3.size() << endl;
if(v3.size()>0)
{
for (auto c : v3)
{
cout << c << " ";
}
cout << endl;
}
vector<int>v4{
10 };
cout << "v4.size" << v4.size() << endl;
if(v4.size()>0)
{
for (auto c : v4)
{
cout << c << " ";
}
cout << endl;
}
vector<int>v5{
10,42 };
cout << "v5.size" << v5.size() << endl;
if(v5.size()>0)
{
for (auto c : v5)
{
cout << c << " ";
}
cout << endl;
}
vector<string>v6{
10 };
cout << "v6.size" << v6.size() << endl;
if(v6.size()>0)
{
for (auto c : v6)
{
cout << c << " ";
}
cout << endl;
}
vector<string>v7{
10,"hi" };
cout << "v7.size" << v7.size() << endl;
if(v7.size()>0)
{
for (auto c : v7)
{
cout << c << " ";
}
cout << endl;
}
system("pause");
return 0;
}
3.17
#include<iostream>
using namespace std;
#include<vector>
#include<string>
#include<cctype>
int main()
{
vector<string> v;
string i = "";
string cont = "y";
cout << "请输入字符串" << endl;
while (cin >> i)
{
v.push_back(i);
cout << "继续添加y 停止n" << endl;
cin >> cont;
if (cont != "y")
{
break;
}
}
for (auto& ci : v)
{
for (auto& zi : ci)
{
zi = toupper(zi);
}
cout << ci << endl;
}
cout << endl;
system("pause");
return 0;
}
3.20
#include<iostream>
using namespace std;
#include<vector>
#include<string>
#include<cctype>
int main()
{
vector<int> v;
int i = 0;
string cont = "y";
cout << "请输入整数" << endl;
while (cin >> i)
{
v.push_back(i);
cout << "继续添加y 停止n" << endl;
cin >> cont;
if (cont != "y")
{
break;
}
}
for (decltype(v.size()) i = 0; i < v.size() - 1; i+=2)
{
cout << v[i] + v[i + 1] << endl;
}
if (v.size() % 2 != 0)
{
cout << v[v.size()-1] << endl;
}
cout << endl;
system("pause");
return 0;
}
#include<iostream>
using namespace std;
#include<vector>
#include<string>
#include<cctype>
int main()
{
vector<int> v;
int i = 0;
string cont = "y";
cout << "请输入整数" << endl;
while (cin >> i)
{
v.push_back(i);
cout << "继续添加y 停止n" << endl;
cin >> cont;
if (cont != "y")
{
break;
}
}
for (decltype(v.size()) i = 0; i < v.size() / 2 ; i++)
{
cout << v[i] + v[v.size()-1-i] << endl;
}
if (v.size() % 2 != 0)
{
cout << v[v.size()/2] << endl;
}
cout << endl;
system("pause");
return 0;
}
3.21
#include<iostream>
using namespace std;
#include<vector>
#include<string>
int main()
{
vector<int>v1;
cout << "v1.size" << v1.size() << endl;
if (v1.begin() != v1.end())
{
for (vector<int>::iterator it = v1.begin(); it != v1.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
vector<int>v2(10);
cout << "v2.size" << v2.size() << endl;
if (v2.begin() != v2.end())
{
for (vector<int>::iterator it = v2.begin(); it != v2.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
vector<int>v3(10, 42);
cout << "v3.size" << v3.size() << endl;
if (v3.begin() != v3.end())
{
for (vector<int>::iterator it = v3.begin(); it != v3.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
vector<int>v4{
10 };
cout << "v4.size" << v4.size() << endl;
if (v4.begin() != v4.end())
{
for (vector<int>::iterator it = v4.begin(); it != v4.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
vector<int>v5{
10,42 };
cout << "v5.size" << v5.size() << endl;
if (v5.begin() != v5.end())
{
for (vector<int>::iterator it = v5.begin(); it != v5.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
vector<string>v6{
10 };
cout << "v6.size" << v6.size() << endl;
if (v6.begin() != v6.end())
{
for (vector<string>::iterator it = v6.begin(); it != v6.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
vector<string>v7{
10,"hi" };
cout << "v7.size" << v7.size() << endl;
if (v7.begin() != v7.end())
{
for (auto it = v7.begin(); it != v7.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
system("pause");
return 0;
}
3.22
#include<iostream>
using namespace std;
#include<vector>
#include<string>
int main()
{
vector<string> text;
string s;
cout << "请输入字符串" << endl;
while (getline(cin, s))
{
text.push_back(s);
}
for (auto it = text.begin(); it != text.end() && !it->empty(); it++)
{
for (auto it2 = it->begin(); it2 != it->end(); it2++)
{
*it2 = toupper(*it2);
}
cout << *it << endl;
}
system("pause");
return 0;
}
3.23
#include<iostream>
using namespace std;
#include<vector>
#include<ctime>
#include<cstdlib>
int main()
{
vector<int>v;
srand((unsigned int)time(NULL));
cout << "请输入整数" << endl;
for (int i = 0; i < 10; i++)
{
v.push_back(rand() % 1000);
}
for (auto it = v.begin(); it != v.end(); it++)
{
cout << *it << endl;
}
cout << "-----------" << endl;
for (auto it = v.begin(); it != v.end(); it++)
{
*it *= 2;
cout << *it << endl;
}
system("pause");
return 0;
}
3.24
#include<iostream>
using namespace std;
#include<vector>
#include<string>
#include<cctype>
int main()
{
vector<int> v;
int i = 0;
string cont = "y";
cout << "请输入整数" << endl;
while (cin >> i)
{
v.push_back(i);
cout << "继续添加y 停止n" << endl;
cin >> cont;
if (cont != "y")
{
break;
}
}
if (v.begin() == v.end())
{
cout << "bleak" << endl;
}
for (auto it=v.begin();it!=v.end()-1;it=it+2)
{
cout << *it + *(it+1) << endl;
}
if ((v.end() - v.begin()) % 2 != 0)
{
cout << *(v.end()-1) << endl;
}
cout << endl;
system("pause");
return 0;
}
#include<iostream>
using namespace std;
#include<vector>
#include<string>
#include<cctype>
int main()
{
vector<int> v;
int i = 0;
string cont = "y";
cout << "请输入整数" << endl;
while (cin >> i)
{
v.push_back(i);
cout << "继续添加y 停止n" << endl;
cin >> cont;
if (cont != "y")
{
break;
}
}
if (v.begin() == v.end())
{
cout << "bleak" << endl;
}
for (auto it=v.begin();it!=v.begin()+(v.end()-v.begin())/2; it++)
{
cout << *it + *(v.begin()+(v.end() - it)-1) << endl;
}
if ((v.end() - v.begin()) % 2 != 0)
{
cout << *(v.begin() + (v.end() - v.begin()) / 2) << endl;
}
cout << endl;
system("pause");
return 0;
}
3.25
#include<iostream>
using namespace std;
#include<vector>
int main()
{
vector<unsigned>v(11);
unsigned grade;
vector<unsigned>::iterator it = v.begin();
while (cin >> grade)
{
if (grade <= 100)
{
*(it + grade/10)+=1;
}
}
cout << "各个分数段人数分布：" << endl;
for (auto its = v.begin(); its != v.end(); its++)
{
cout << *its << " ";
}
cout << endl;
system("pause");
return 0;
}
3.30
#include<iostream>
using namespace std;
#include<vector>
int main()
{
const int sz = 10;
int arr[sz];
for (int i = 0; i < 10; i++)
{
arr[i] = i;
}
for (int val : arr)
{
cout << val << " ";
}
cout << endl;
system("pause");
return 0;
}
3.31
#include<iostream>
using namespace std;
int main()
{
const int sz = 10;
int arr[sz];
int brr[sz];
for (int i = 0; i < 10; i++)
{
arr[i] = i;
}
for (int i = 0; i < 10; i++)
{
brr[i] = arr[i];
}
for (int val : brr)
{
cout << val << " ";
}
cout << endl;
system("pause");
return 0;
}
3.32
#include<iostream>
using namespace std;
#include<vector>
int main()
{
vector<int>v1;
vector<int>v2;
for (int i = 0; i < 10; i++)
{
v1.push_back(i);
}
for (int i = 0; i < 10; i++)
{
v2.push_back(v1[i]);
}
for (auto val : v2)
{
cout << val << " ";
}
cout << endl;
system("pause");
return 0;
}
3.33
#include<iostream>
using namespace std;
int main()
{
const int sz = 10;
int arr[sz];
for (int i = 0; i < sz; i++)
{
arr[i] = i;
}
cout << "数组中有数字为：" << endl;
for (int j : arr)
{
cout << j << " ";
}
cout << endl;
for (int *p = begin(arr); p != end(arr); p++)
{
*p = 0;
}
cout << "后数组中有数字为：" << endl;
for (int j : arr)
{
cout << j << " ";
}
cout << endl;
}
3.34
#include<iostream>
using namespace std;
#include<cstdlib>
int main()
{
const int sz = 10;
int arr1[sz], arr2[sz];
srand((unsigned int)time(NULL));
for (int i = 0; i < sz; i++)
{
arr1[i] = rand() % 10;
arr2[i] = rand() % 10;
}
cout << "arr1:" << endl;
for (int i = 0; i < sz; i++)
{
cout << arr1[i] << " ";
}
cout << endl;
for (int i = 0; i < sz; i++)
{
cout << arr2[i] << " ";
}
cout << endl;
for (int j = 0; j < sz; j++)
{
if (arr1[j] != arr2[j])
{
cout << "different" << endl;
break;
}
}
}
You can also read books, use while statements, and use pointers and library functions begin end;
3.41
#include<iostream>
using namespace std;
#include<cstring>
#include<vector>
int main()
{
int arr[] = {
1,2,3,4,5,6,7,8,9 };
vector<int>v(begin(arr), end(arr));
for (auto val : v)
{
cout << val << endl;
}
system("pause");
return 0;
}
3.42
#include<iostream>
using namespace std;
#include<cstring>
#include<vector>
int main()
{
int arr1[] = {
1,2,3,4,5,6,7,8,9 };
vector<int>v(begin(arr1), end(arr1));
for (auto val : v)
{
cout << val << endl;
}
int* arr2 = new int[v.size()];
int i = 0;
for (auto val : v)
{
arr2[i] = val;
i++;
}
for (int j=0;j<v.size();j++)
{
cout << arr2[j] << endl;
}
system("pause");
return 0;
}
3.43
#include<iostream>
using namespace std;
int main()
{
int ia[3][4] = {
{
0,1,2,3},
{
4,5,6,7},
{
8,9,10,11}
};
for (int (&row)[4] : ia) {
for (int &val : row) {
cout << val << " ";
}
cout << endl;
}
cout << "--------" << endl;
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 4; j++) {
cout << ia[i][j] << " ";
}
cout << endl;
}
cout << "--------" << endl;
for (int(*p)[4] = ia; p != end(ia); p++) {
for (int* q = *p; q != end(*p); q++) {
cout << *q << " ";
}
cout << endl;
}
system("pause");
return 0;
}