16進制整數轉化成字符串

    Linux下gcc沒有itoa，項目要用到16位地址轉換成字符經過串口發送，只能本身動手
                              

int itoa(int val, char *buf,int size) const//16進制
{
    char *p = buf;
    char t = '0';
    int len = 0;
    int slen = size;
    while(val > 0 && len < slen) {
        t = val % 16;
        val -= t;
        val /= 16;
        if (t > 9) {
            *p++ = t- 10 + 'a';
        } else {
            *p++ = t + '0';
        }
        ++len;
    }
    for (int i = 0;i < len/2;++i) {
        char c = buf[i];
        buf[i] = buf[len-1-i];
        buf[len-1-i] = c;
    }
    buf[len] = '\0';
    return len;
}