C程序设计语言学习--十六进制转换等值的整型值

十六进制转换等值的整型值：

#define YES 1
#define NO 0

int htos(int s[])
{
    int hexdigit,n,i,inhex;
    i = 0;
    if(s[i] == 0){
        i ++;
        if(s[i] == 'x' || s[i] == 'X'){
            i ++;
        }
    }
    
    n = 0;
    inhex = YES;
    for(;inhex == YES;i ++){
        if(s[i] => '0' && s[i] <= 9){
            hexdigit = s[i] - '0';
        }else if(s[i] >= 'a' && s[i] <= 'f'){
            hexdigit = s[i] - 'a' + 10;
        }else if(s[i] >= 'A' && s[i] <= 'F'){
            hexdigit = s[i] - 'A' +10;
        }else{
            inhex = NO;
        }
        if(inhex == YES){
            n = n * 16 + hexdigit;
        }
    }
    return n;
}