逆反字符串

求问大佬这段代码啥意思啊？？
题目奉上：
输入：#
      ldrow
      olleh
      #
输出：world
      holle

#include<stdio.h>
#include<stdlib.h>
int main()
{
    char c;
    int i, j, k, b1;
    char a[100];
    char b[100];
    c = getchar();
    while (c == '#')
    {
        getchar();        //收回车
        b1 = 0;
        if ((c = getchar()) == '#') break;     //如果是# 退出循环
        else
        {
            a[0] = c; i = 0; j = 0;          //设置i，j为单词起始，结尾
            for (k = 1; (c = getchar()) != '#'; k++)
            {
                a[k] = c;
                if (c == ' ' || c == '\n')
                {
                    j = k - 1;                       //a[k]==' '||'\n'    a[j]=a[k-1]为单词结尾
                    for (; j >= i; j--, b1++)
                    {
                        b[b1] = a[j];
                    }
                    b[b1] = c;
                    b1++;
                    i = k + 1;            //k+1为下一单词开头   
                }

            }

        }
        for (b1 = 0; b1 < i - 1; b1++)
            printf("%c", b[b1]);
        printf("\n");
        getchar();                      //收回车
        c = getchar();
    }
    return 0;
}