Question

Here’s my issue:

I have written a function to detect if a string is hex based off of the “0x####” format:

int lc3_hashex(char *str)
{
    int val = 0;      
    char *to;
    to = strndup(str+2, 10);
    val = sscanf(to, "%x", &val); 
    if (val)
    {
        return val;
    }

    return 0;
}

Assuming the parameter is of the form “0x####”, it returns the decimal version of the post “0x” numbers. But is there any built in way (or a way I am just overseeing) to get the integer value of the hexidecimal number “0x4000” as opposed to the integer value of “4000”?

Thanks.

Answer 1

Use strtol from stdlib.h and specify the base as 16.

The only downside is that this function returns 0 upon failure, so you’ll want to check to make sure the input to it is not 0.