字符串旋转实现

首先把字符串旋转分解成一个一个轮流的移动.

由于这里实现中每次移动会是这样:   比如 src = "abcdefg"  向左移动3位后 就变成了 defgcba, 实际结果是defgabc;

所以才额外添加了一个if 判断语句，用来保证后面的 元素的顺序。　　　

　　　　　　　

char *
str_whirl(char *src, int len, int k)
{
    int index_i, index_j, index_x;
    char tmp, *tmp_dest;

    tmp_dest = src;

    k %= len;

    if(src == NULL || k == 0)
        return tmp_dest;

    index_j = 1;
    while(k)
    {
        for(index_i = 0; index_i < len - index_j; index_i++)
        {
            tmp = src[index_i];
            src[index_i] = src[index_i+1];
            src[index_i+1] = tmp;
            if(index_j > 1 && index_i == len - index_j -1)
            {

                for(index_x = index_i + 1; index_x < len - 1; index_x++)
                {
                    tmp = src[index_x];
                    src[index_x] = src[index_x+1];
                    src[index_x + 1] = tmp;
                }
            }

        }

        k--;
        index_j++;
    }

    return tmp_dest;
}

int
main(int argc, char *argv[])
{
    char src[10] = "3abcdefg12";

    char *tmp;
    printf("the src before -> %s\n", src);
    tmp = str_whirl(src, 10, 3);

    printf("\tsrc = %s\n", src);
    printf("\ttmp = %s\n", tmp);

    return;
}