递归实现二进制转十进制

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

void binary_to_decimal(char *s, long dec)
{
    if( *s == ‘\0‘ )
        printf("Decimal: %ld\n",dec);
    else
    {
        if( *s != ‘0‘ && *s != ‘1‘ )
        {
            printf("Illegal Input.\n");
            exit(1);
        }
        dec = dec*2 + (*s -‘0‘);
        binary_to_decimal(s+1,dec);
    }
}

int main(void)
{
    char s[101];

    printf("Please input a binary number: ");
    scanf("%s",s);
    binary_to_decimal(s,0);

    return 0;
}