CPP_Basic_Code_P5.1-PP5.9.10

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##CPP_Basic_Code_P5.1-PP5.9.10

//  The Notes Created by Z-Tech on 2017/2/17.
//	All Codes Boot on 《C++ Primer Plus》V6.0
//  OS：MacOS 10.12.4
//  Translater：clang/llvm8.0.0 &g++4.2.1
//  Editer：iTerm 2&Sublime text 3
//  IDE: Xcode8.2.1&Clion2017.1

//P5.1
#include <iostream>
int main()
{
    using namespace std;
    int i;
    for (i=0;i<5;i++)
    //注意循环初始化、循环测试和循环更新括号内全部是分号！不是逗号！
        cout<<"C++ know loops.\n";
    cout<<"C++ Know when to stop.\n";
    return 0;
}

//P5.2
#include <iostream>
int main()
{
    using namespace std;
    cout<<"Enter the starting countdown value: ";
    int limit;
    cin>>limit;
    int i;
    for (i=limit;i;i--)
    //自减计算，到0为止，直接输入0则会立即退出，不执行循环
        cout<<"i = "<<i<<"\n";
    cout<<"Done now that i = "<<i<<"\n";
    return 0;
}

//P5.3
#include <iostream>
int main()
{
    using namespace std;
    int x;
    cout<<"The expression x=100 has the value ";
    cout<<(x=100)<<endl;
    cout<<"Now x="<<x<<endl;
    cout<<"The expression x<3 has the value ";
    cout<<(x<3)<<endl;
    cout<<"The expression x>3 has the value ";
    cout<<(x>3)<<endl;
    
    cout.setf(ios_base::boolalpha);//C++11新特性，bool输出
    cout<<"The expression x<3 has the value ";
    cout<<(x<3)<<endl;
    cout<<"The expression x>3 has the value ";
    cout<<(x>3)<<endl;
    return 0;
}

//P5.4
#include <iostream>
const int ArSize=16;//使用常量便之后修改
int main()
{
    long long factorials[ArSize];//创建long long类型的数组
    factorials[1]=factorials[0]=1LL;
    //初始化数组的第1和第2个元素为long long型的1
    //原因是0！和1！都等于1，而每个元素存储对应的i!
    for (int i=2;i<ArSize;i++)//
        factorials[i]=i*factorials[i-1];
    //i=2开始，因此从2！开始计算，即第三个元素开始计算，一直计算到15！
    for (int i=0;i<ArSize;i++)
        std::cout<<i<<"!="<<factorials[i]<<std::endl;
    return 0;
}

//P5.5
#include <iostream>
int main()
{
    using std::cout;//使用using声明，而不是using编译指令
    using std::cin;
    using std::endl;
    cout<<"Enter an integer: ";
    int by;
    cin>>by;
    cout<<"Counting by "<<by<<"s:\n";
    for (int i=0;i<100;i=i+by)
    //注意内部条件的大于小于号不要错误输入成<<和>>
        cout<<"i= "<<i<<endl;
    return 0;
}

//P5.6
#include <iostream>
#include <string>
int main()
{
    using namespace std;
    cout<<"Enter a word: ";
    string word;
    cin>>word;

    for (int i=word.size()-1;i>=0;i--)
    //此处i的初始化并未考虑空值字符
        cout<<word[i];//数组法访问string并反向打印
    cout<<"\nBye.\n";
    return 0;
}

//P5.7
#include <iostream>
int main()
{
    using std::cout;
    int a=20,b=20;
    cout<<"a= "<<a<<"  "<<" b= "<<b<<"\n";
    cout<<"a++= "<<a++<<"  "<<" ++b= "<<++b<<"\n";
    //a++是后加，当时不变事后变，++b是先加，值立刻即改变
    cout<<"a= "<<a<<"  "<<" b= "<<b<<"\n";
    return 0;
}

//P5.8
#include <iostream>
int main()
{
    using namespace std;
    cout<<"The Amazing accounts will sum and average ";
    cout<<"Five numbers for you.\n";
    cout<<"Please enter five values:\n";
    double number;
    double sum=0.0;
    //此处定义了求和sum和存放输入的number
    for (int i=1;i<=5;i++)//精确控制了五次循环
    {
        cout<<"Value "<<i<<": ";
        cin>>number;
        sum+=number;
    }//{}内为代码块，被C++视为一条语句
    cout<<"Five exquisite choices indeed! ";
    cout<<"They sum to "<<sum<<endl;
    cout<<"And average to "<<sum/5<<".\n";//求出平均值
    cout<<"The Amazing Account bid you adieu!\n";
    return 0;
}

//P5.9
#include <iostream>
#include <string>
int main()
{
    using namespace std;
    cout<<"Enter a word: ";
    string word;
    cin>>word;
    char temp;
    int i,j;
    for (j=0,i=word.size()-1;j<i;--i,++j)//此处不应该有分号！！！
    {
        temp=word[i];//将最后一个字符赋值给temp
        word[i]=word[j];//将string word第一个字符赋值给最后一个元素
        word[j]=temp;
        //将temp中的最后一个字符赋值给string word的第一个元素
    }
    cout<<word<<"\nDone\n";
    cout<<word[0];//数组式访问string第一个元素(字符)
    return 0;
}

//P5.10
#include <iostream>
int main()
{
    using namespace std;
    int quizscores[10]={20,20,20,20,20,19,20,18,20,20};
    cout<<"Doing it right:\n";
    int i;
    for (i=1;quizscores[i]==20;i++)
    //使用==比较是否相等，相等为true继续，不等为false跳出
        cout<<"quiz "<<i<<" is a 20\n";
    //cout<<"Doing it dangerously wrong:\n";
    //for (i=1;quizscores=20;i++)
    //此处并未使用==将十分危险，因为表达式值被赋值锁定为20
    //始终为true将陷入死循环
    //cout<<"quiz "<<i<<" is a 20\n";
    return 0;
}

//P5.11
#include <iostream>
#include <cstring>
int main()
{
    using namespace std;
    char word[5]="?ate";//定义了数组，将未知首字符设置为？
    for (char ch='a';strcmp(word,"mate");ch++)
    //使用strcmp()函数比较，字符串一样时跳出循环
    //需要注意的是循环检测这部分的句子实际是strcmp()!=0的简写，含义一样
    //两个字符串一致为false，否则为true，true则继续执行
    {
        cout<<word<<endl;
        word[0]=ch;//将自增后的字符赋值给word首字母
    }
    cout<<"After loop ends.Word is "<<word<<endl;
    return 0;
}

//P5.12
#include <iostream>
#include <string>
int main()
{
    using namespace std;
    string word="?ate";
    for (char ch='a';word!="mate";ch++)
    //不等于则为true，继续执行，使用C++ string类
    {
        cout<<word<<endl;
        word[0]=ch;
    }
    cout<<"After loop ends.Word is "<<word<<endl;
    return 0;
}

//P5.13
#include <iostream>
const int ArSize=20;//可使用#include <string>
int main()
{
    using namespace std;
    char name[ArSize];
    cout<<"Your first name,please: ";
    cin>>name;
    cout<<"Here is your name,verticalized and ASCIIized:\n";
    int i=0;
    while (name[i]!='\0')
    //可直接用name[i]即可，非0为true，遇空字符为0，false
    //while循环无需初始化和循环更新参数
    // !=空字符就继续，也就是到末尾前一直循环
    //字符串自带结尾空字符标记，所以无需知道字符串长度
    {
        cout<<name[i]<<": "<<int(name[i])<<endl;
        i++;//while循环应当在循环体内调整测试条件参数
    }
    return 0;
}

//P5.14
#include<iostream>
#include <ctime>
int main()
{
    using namespace std;
    cout<<"Enter the delay time,in seconds: ";
    float secs;
    cin>>secs;
    clock_t delay=secs*CLOCKS_PER_SEC;
    //该常量描述每秒系统时间单位数，乘以秒数就是所需延迟的系统时间
    cout<<"Starting\a\n";//\a是转义的振铃符
    clock_t start=clock();//设置时间计时起始点
    while (clock()-start<delay)
    //测试当前时间减去起始时间的间隔是否等于所需延迟的系统时间
        ;//循环体为空
    cout<<"Done！\a\n";
    return 0;
    //此程序以系统时间单位为单位，避免在每轮循环中将系统时间转换为秒
}

//P5.15
#include <iostream>
int main()
{
    using namespace std;
    int n;
    cout<<"Enter number in the range 1-10 to find ";
    cout<<"My favorite number\n";
    do//这种循环是出口条件循环，至少执行一次循环体
    {
        cin>>n;
    }while(n!=7);//表达式成立则继续，否则退出
    cout<<"Yes,7 is My favorite number!\n";
    return 0;
}

//P5.16
#include <iostream>
int main()
{
    using namespace std;
    char ch;
    int count=0;//将字符数初始化为0
    cout<<"Enter characters;Enter # to quit:\n";
    cin>>ch;//读入第一个字符
    while (ch!='#')
    {
        cout<<ch;//cin使得输入的空格将会被忽略，也不会被计数
        ++count;//立刻增加
        cin>>ch;
    }
    cout<<endl<<count<<" characters read\n";
    return 0;
}

//P5.17
#include <iostream>
int main()
{
    using namespace std;
    char ch;
    int count=0;//将字符数初始化为0
    cout<<"Enter characters;Enter # to quit:\n";
    cin.get(ch);//使用cin.get()将不会忽略空格等字符
    while (ch!='#')
    {
        cout<<ch;
        ++count;//立刻增加
        cin.get(ch);
    }
    cout<<endl<<count<<" characters read\n";
    return 0;
}

//P5.18
#include <iostream>//Clion可能不支持键盘模拟EOF
int main()
{
    using namespace std;
    int ch;
    int count=0;
    cin.get(ch);
    while (cin.fail()==false)
    {
        cout<<ch;//强制类型转换为char类型
        ++count;
        cin.get(ch);
    }
    cout<<endl<<count<<" Characters read.\n";
    return 0;
}

//P5.19
#include <iostream>//Clion可能不支持键盘模拟EOF
int main(void)
{
    using namespace std;
    int ch;
    int count=0;
    while ((ch=cin.get())!=EOF)
    //测试ch的值是否为EOF，true则结束，否则继续
    {
        cout.put(char(ch));//强制类型转换为char类型
        ++count;
    }
    cout<<endl<<count<<" Characters read.\n";
    return 0;
}

//P5.20
#include <iostream>
const int Cities=5;
const int Years=4;
int main()
{
    using namespace std;
    const char* cities[Cities]//创建指针数组分别指向五个字符串
    {
         "Gribble City",
         "Gribbletown",
         "New Gribble",
         "San Gribble",
         "Gribble Vista"
    };
    int maxtemps[Years][Cities]//创建2d数组，有Years行，Cities列
    {
        {96,100,87,101,105},//注意里面全部是逗号！！
        {96,98,91,107,104},//且每个子数组都用花括号{}包围
        {97,101,93,108,107},
        {98,103,95,109,109}//最后一行的子数组后面没有逗号

    };
    cout<<"Maximun tempratures for 2008-2011\n\n";
    for (int city=0;city<Cities;++city)//城市数是5大于年份数4，故此先for大的，即城市数(列)
    {
        cout<<cities[city]<<":\t";//\t是制表符，这里实际上输出城市名称
        for (int year=0;year<Years;++year)//循环年份数
            cout<<maxtemps[year][city]<<"\t";
            //这里输出同一城市四年最高温度，也就是列输出
        cout<<endl;
    }
    return 0;
}

//PP5.9.1
#include <iostream>
int main()
{
    using namespace std;
    cout<<"Enter the first intger: ";
    int n1;//这里默认n1<=n2
    cin>>n1;
    cout<<"\nEnter the last integer: ";
    int n2;
    cin>>n2;
    int sum=0;//sum需在外部定义,才不会每次循环都被初始化为0
    for (n1;n1<=n2;n1++)//这里n1++或者++n1都无所谓
        sum+=n1;
    cout<<"\nSum: "<<sum<<endl;
    return 0;
}

//PP5.9.2
#include <iostream>
#include <array>
int main()
{
    using namespace std;
    cout.setf(ios_base::fixed,ios_base::floatfield);//修复小数点形式
    const int ArSize=16;
    array<long double,ArSize> factrials;//array中的ArSize不能是变量！！
    factrials[1]=factrials[0]=1;//设置初始第一个和第二个元素
    int i=2;
    long double Result=0;
    for (i;i<=ArSize;i++)
    {
        factrials[i]=i*factrials[i-1];
        Result=factrials[i];
    }
    cout<<i-1<<"!= "<<Result<<endl;

    return 0;
}

//PP5.9.3
#include <iostream>
int main()
{
    using namespace std;
    cout<<"Please enter a number and enter '0' to quit: ";
    long double number=0;
    int count=0;//设定计数器
    int sum=0;//设定求和器
    cin>>number;
    while (number!=0)
    {
        ++count;
        sum+=number;//求和的关键
        cout<<"Sum of all your input is "<<sum<<endl;
        cin>>number;
    }
    cout<<endl<<count<<" times read.";//输入的次数也就是循环体执行的次数
    return 0;
}

//PP5.9.4
#include<iostream>
int main()
{
    using namespace std;
    int count=1;
    int D_interests;
    double C_interests=100;
    do
    {
        D_interests=100+(10*count);//Daphne是单利计算，每年固定10$
        C_interests*=1.05;//Cleo是复利计算，每年都是实际金额的1.05倍
        // 实际上应该使用次方计算，但是巧妙利用C++的*=和循环成功实现计算
        count++;//年份计数器
    }
    while (D_interests>C_interests);
    cout<<"Need "<<count-1<<" Years.";
    //因为count初值为1，且循环结束时多+1，故此处应该-1
    return 0;
}

//PP5.9.5
#include <iostream>
#include <string>
int main()
{
    using namespace std;
    int m_books[12];
    string Month[12]
            {"January","February","March","April",
            "May","June","July","August", "September",
             "October","November","December"};
    int m_all=0;//求和工具设定初始化
    for (int i=0;i<12;i++)
    {
        cout << "Please enter sales of "<<Month[i]<<": ";
        cin>>m_books[i];
        cout<<"The sales of "<<Month[i]<<" is: "<<m_books[i]<<endl;
        m_all+=m_books[i];
    }
    cout<<"This year the books you have saled in total: "<<m_all<<endl;
    return 0;
}

//PP5.9.6
#include <iostream>
const int years=3;//只需修改此处即可调整不同的年份
const int Monthx=12;
int main()
{
    using namespace std;
    const char* Month[Monthx]//定义月份字符串，使用指针数组
            {   "January", "February","March","April",
                "May","June","July","August", "September",
                "October","November","December"
            };
    int Books_sales [years][Monthx]//定义N年各个月销售数据的2D数组
            {};//为空则全部初始化为0
    int y_all[years] {0};//定义每年销售额总数计数数组
    int m_all=0;//定义全部年份的销售额总数计数器
    for (int i=1;i<(years+1);i++)
    {
        cout<<"Please enter sales of no."<<i<<" year ";
        for (int j=0;j<Monthx;j++)
        {
            cout<<Month[j]<<": ";
            cin>>Books_sales[i][j];//一个个分别存储入2D数组
            cout<<"The sales of no."<<i<<" year "
                <<Month[j]<<" is: "<<Books_sales[i][j]<<endl;//回显输入
            y_all[i-1]+=Books_sales[i][j];//求出当年总额后存入年份数组
            m_all+=Books_sales[i][j];//持续累计销售总额
        }
    }
    for (int i=0;i<years;i++)//年度销售数据报告
        cout<<"The no."<<i+1<<" year you sales: "<<y_all[i]<<endl;
    cout<<years<<" year that books you have saled in total: "<<m_all<<endl;//最终总数
    return 0;
}

//PP5.9.7_V1
#include <iostream>
struct car//结构声明
{
    char Product_make[15];
    int Product_year;
};
int main()
{
    using namespace std;
    cout<<"How many cars do you wish to catalog?";
    int car_number;
    cin>>car_number;
    car* xv=new car[car_number];//创建动态指针数组
    for (int i=0;i<car_number;i++)
    {

        cout<<"Car #"<<i+1<<": "<<endl;
        cout<<"Please enter the make: ";
        cin.get();//十分关键！！！此时输入队列中有回车
        cin.getline(xv[i].Product_make,15);//注意动态指针数组的读取方式
        cout<<"Please enter the year made: ";
        cin>>xv[i].Product_year;
    }
    cout<<"\nHere is your collections: \n";
    for (int i=0;i<car_number;i++)
    {
        cout<<xv[i].Product_year<<" "<<xv[i].Product_make<<endl;
    }
    delete [] xv;
    return 0;
}

//PP5.9.7_V2
#include <iostream>
#include <string>
struct car//结构声明
{
    std::string Product_make;
    int Product_year;
};
int main()
{
    using namespace std;
    cout<<"How many cars do you wish to catalog? ";
    int car_number;
    cin>>car_number;
    car* xv=new car[car_number];//创建动态指针数组
    for (int i=0;i<car_number;i++)
    {

        cout<<"Car #"<<i+1<<": "<<endl;
        cout<<"Please enter the make: ";
        cin.get();//十分关键！！！此时输入队列中有回车
        getline(cin,xv[i].Product_make);//注意动态指针数组里string的读取方式
        cout<<"Please enter the year made: ";
        cin>>xv[i].Product_year;
    }
    cout<<"\nHere is your collections: \n";
    for (int i=0;i<car_number;i++)
    {
        cout<<xv[i].Product_year<<" "<<xv[i].Product_make<<endl;
    }
    delete [] xv;
    return 0;
}

//PP5.9.8
#include <iostream>
#include <cstring>
int main()
{
    using namespace std;
    char words[15];
    int count=0;//单词循环计数器
    cout<<"Enter the words(to stop,type the word done): \n";
    while (strcmp(words,"done"))//使用strcmp函数执行比较，不同继续直到相同时跳出
    {
        count++;
        cin>>words;
    }
    cout<<"You entered a total of "<<(count-1)<<" words.";
    return 0;
}

//PP5.9.9
#include <iostream>
#include <string>
int main()
{
    using namespace std;
    string words;
    int count=0;//单词循环计数器
    cout<<"Enter the words(to stop,type the word done): \n";
    while (words!="done")//使用string关系运算符比较，不同继续为true，直到相同时false跳出
    {
        count++;
        cin>>words;
    }
    cout<<"You entered a total of "<<(count-1)<<" words.";
    return 0;
}

//PP5.9.10
#include <iostream>
int main()
{
    using namespace std;
    int i,j,n;
    cout<<"Please enter the number of lines: ";
    cin>>n;
    for (i=1;i<=n;i++)//循环嵌套的关键：子循环的判定条件必须是主循环核心变量的关系式！！！
    {
        for (j=1;j<=n-i;j++)//第一次循环4次，然后3、2、1、0
            cout<<".";
        for (j=1;j<i+1;j++)//第一次循环1次，然后2，3，4，5
            cout<<"*";
        cout<<endl;//每一行需要分隔
    }
    return 0;
}