c语言实现字符串转换为十进制数字

阳光穿透心脏的1/2处 2022-12-10 10:12 300阅读 0赞

int sysMyHex10(char *buf)
{
    char *tempbuf = buf;
    char *startbuf = NULL;
    int start = 0;
    int ret = 0;
    int i = 0;
    int base = 1;
    if(buf == NULL)
        return 0;
    while(*tempbuf != '\0')
    {
        if(((*tempbuf >= '0') && (*tempbuf <= '9'))
                  || ((*tempbuf == '-') && (start == 0)))
        {
            if(start == 0)
            {
                startbuf = tempbuf;
            }
            start = 1;
        }
        else
        {
            if(start == 1)
                break;
        }
        tempbuf++;
    }
    if(startbuf != NULL)
    {
        if(*startbuf == '-')
        {
            startbuf++;
            while(startbuf != tempbuf)
            {
                base = 1;
                for(i = 0; i < (tempbuf - startbuf - 1); i++)
                    base = base * 10;
                ret = ret + (*startbuf - '0') * base;
                startbuf++;
            }
            return 0 - ret;
        }
        else
        {
            while(startbuf != tempbuf)
            {
                base = 1;
                for(i = 0; i < (tempbuf - startbuf - 1); i++)
                    base = base * 10;
                ret = ret + (*startbuf - '0') * base;
                startbuf++;
            }
            return ret;
        }
    }
    return 0;
}