Description
Encapsulates a string class for storing strings and processing related functions, supporting the following operations:
1. STR::STR() constructor: Creates an empty string object.
2. STR::STR(const char *) construction method: Create a string object, the content of the string is given by the parameter.
3. STR::length() method: Returns the length of the string.
4. STR::putline() method: output the content of the string and wrap it in a new line.
5. The operators "+" and "+=" represent the concatenation of two strings. The rules are:
c = a + b means that the characters in string c are the concatenation of a and b: the result of "a+b" is a new string with the contents of strings a and b unchanged.
a += b means that the characters in string a are the concatenation of a and b: the contents of string b remain unchanged
-----------------------------------------------------------------------------
You design a string class STR so that the main() function can run correctly.
See append.cc for the function call format.
The main() function has been given in append.cc.
-----------------------------------------------------------------------------
Invalid Word error: "string", "vector", etc. are disabled.
Input
The input has several lines, each with a string.
Output
Each set of test data corresponds to a line of output, which contains two parts, the first is an integer representing the length of the input string, and the second is the input string, separated by a space. See sample for format.
Sample Input
Sample Output
#include<bits/stdc++.h>
using namespace std;
void f(char *s1,char *s2,int length)//令s1=s2,length为s2的长度
{
int i;
for( i=0;i<length;i++)
{
s1[i]=s2[i];
}
s1[i]=0;
}
class STR
{
public:
STR()
{
l=0;
}
STR(char *p)
{
int i;
for(i=0;p[i]!=0;i++)
{
}l=i;
s=new char[l+1];
f(s,p,l);
}
~STR()
{
delete []s;
}
int length()
{
return l;
}
void putline()
{
cout<<s;
cout<<endl;
}
STR &operator+=(STR &p)//加&是因为没有写构造函数，成员有指针。
{
//思路是先构造一个q存左操作数，左操作数new完后，再将q和p复制过去。
int j=l;
STR q(s);
l=l+p.l;
delete []s;
s=new char[l+1];
f(s,q.s,q.l);
for(int i=0;i<p.l;i++)
{
s[j++]=p.s[i];
}
s[l]=0;
return *this;
}
friend STR operator+(STR &e,STR &h);
private:
int l;
char *s;
};
STR operator+(STR &e,STR &h)
{
STR temp;
int j=e.l;
temp.l=e.l+h.l;
temp.s=new char[temp.l+1];
for(int i=0;i<e.l;i++)
{
temp.s[i]=e.s[i];
}
for(int i=0;h.s[i]!=0;i++)
{
temp.s[j++]=h.s[i];
}
temp.s[temp.l]=0;
return temp;
}
int main()
{
STR e;
STR h("Hello World!");
STR he = e + h;
cout << he.length() << " ";
he.putline();
cout << e.length() << " ";
e.putline();
cout << h.length() << " ";
h.putline();
e += h;
cout << e.length() << " ";
e.putline();
cout << h.length() << " ";
h.putline();
char s1[100001], s2[100001];
while(gets(s1) != NULL && gets(s2) != NULL)
{
STR str1(s1), str2(s2);
STR str = str1 + str2;
cout << str.length() << " ";
str.putline();
cout << str1.length() << " ";
str1.putline();
cout << str2.length() << " ";
str2.putline();
str2 += str1;
cout << str2.length() << " ";
str2.putline();
cout << str1.length() << " ";
str1.putline();
}
}