c char to int

int x = (int)character - 48;

int x = character - '0'; 

int i = (int)(c - '0');

int i;
char c = 'A'; 
i = (int)c;

#include <sstream>

using namespace std;

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

    double x;
    str >> x;
}