C/C++: Converting hexadecimal value in char to integer

Question

I have hexadecimal values stored as characters:

char A = \'0\';
char B = \'6\';
char C = \'E\';

... I need them coverted to integers. I kno

Answer 1

#include 
#include 


int xtoi(char c)
{
    int v = -1;
    char w=toupper(c);
    if(w >= 'A' && w <= 'F'){
        v = w - 'A' + 0x0A;
    }else if (w >= '0' && w <= '9'){
        v = w - '0';
    }

    return v;
}

int main(int argc,char **argv)
{
    printf("v:%p\n",argc == 2 ? xtoi(argv[1][0]):-1);
    return 0;
}