[C/C++] 16進制字串轉數值

說明:
16進制字串轉數值

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int strtonum(char *p_input)
{
    char *pTmp;
    if ( *p_input == '0' )
    {
        if ( *(p_input + 1) == 'x' || 
                 *(p_input + 1) == 'X' )
        {
            pTmp = p_input + 2;
            return strtoll( pTmp, NULL, 16 );
        }
    }
    
    return strtoll( p_input, NULL, 10 );
}

int main(int argc, char *argv[])
{
    char val[] = "0x30";
    int ret = strtonum(val);
    printf("%s = 0x%x\n", val, ret);
    
    return 0;
}

Result:

0x30 = 0x30