颜色反转

题目链接： http://exercise.acmcoder.com/online/online_judge_ques?ques_id=3340&konwledgeId=40

解题思路： 直接模拟。

#include <bits/stdc++.h>
using namespace std;

int getOrder(char ch)
{
    if (isdigit(ch)) return ch-'0';
    return ch-'A'+10;
}

char getChar(int x)
{
    if (x<10) return '0' + x;
    return 'A' + x - 10;
}

int char2int(char *s)
{
    return getOrder(s[0])*16 + getOrder(s[1]);
}

void int2char(int x, char *s)
{
    int i = x / 16;
    int j = x % 16;
    s[0] = getChar(i);
    s[1] = getChar(j);
}

int main()
{
    char s[10];
    while (scanf("%s", s) != -1)
    {
        int x = char2int(s+1);
        int2char(255-x,s+1);
        x=char2int(s+3);
        int2char(255-x,s+3);
        x=char2int(s+5);
        int2char(255-x,s+5);
        printf("%s
",s);
    }
    return 0;
}