c++ 字符 字符串转数字

相信我 会更快

#include <bits/stdc++.h>
using namespace std;





int main(int argc, char** argv) {
    
    
    
    
    string c2 = "56";
    int a = c2[0] - '0';
    cout << a<<endl;
    char c1 = '7';
    int b = c1 - '0';
    cout << b<<endl;
    
    
    
    return 0;
}