c + convert one char of string to int code example

Example 1: convert char to int c++

char a = '6'; //bounded by 0 and 9
int n1 = a - '0'; 
int n2 = a - 48; 
int n3 = std::stoi(&a);

Example 2: converting char to int in c++

#include <sstream>

using namespace std;

int main()
{
    stringstream str;
    
    str << "1";

    double x;
    str >> x;
}