C++Convert string type to int type

Writing a program needs to convert string to int, so I explored it.

Method 1: atoi function

The atoi function converts a string to an integer, note that you need the stdlib library. So I tried it out:

#include <iostream>
#include <string.h>
#include <stdlib.h>
using namespace std;
int main()
{
 string a="11",b="22";
 cout<<atoi(a)+atoi(b)<<endl;
 return 0;
}

However, I found an error:

Obviously, atoi needs const char*type, and the type I gave above is string, so we need to add an additional function string.c_str(). string.c_str() is a function in the Borland String class, which returns the address of the first character of the current string.

The return value of the c_str() function is const char*, so we add the c_str() function:

#include <iostream>
#include <string.h>
#include <stdlib.h>
using namespace std;
int main()
{
 string a="11",b="22";
 cout<<atoi(a.c_str())+atoi(b.c_str())<<endl;
 return 0;
}

Then it was successful, and I hope everyone can point out any inappropriate things.

That's all for this article. I hope the content of this article can bring you some help in learning or work, and I also hope to get more support for the Yelling Tutorial!

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