C++中将int转变成string和string转变成int

#include<iostream>
#include<string>
using namespace std;
int main()
{
    string s;
    char c[100];
    int m=199;
    itoa(m,c,10);
    s=c;
    s.insert(0,"zhang");
    cout<<s<<endl;
    return 0;


}

#include<iostream>
#include<string>
using namespace std;
int main()
{
    string s="56sd";
    int a=atoi(s.c_str());
    cout<<a<<endl;
    return 0;
}