十六进制转换成char*，double转换成char*

//将十六进制转换成char*
double sss;
char ptrs[256];
sprintf(ptrs, "%x", sss);

int char2int(const char* str) {
    const char* p = str;
    bool neg = false;
    int res = 0;
    if (*str == '-' || *str == '+') 
    { str++; }
    while (*str != 0)
    { 
        if (*str < '0' || *str > '9') 
        { 
            break; 
        }         
        res = res * 10 + *str - '0';
        str++; 
    }
    if (*p == '-') 
    { 
        res = -res;
    }     
    return res;
}