#include <stdio.h>
int main()
{
// 凯撒加密，明文中字母按字母表左移或者右移三位,这里右移
char input[6] = "hello";
char output[6];
int key = 3;
int i,j;
for (i = 0; i < 5; i++)
{
int a = input[i];
a += 3;
output[i] = (char)a;
}
output[i] = ' ';
printf("加密后：%s
", output);
for (j = 0; j < 5; j++)
{
int b = output[j];
b -= 3;
input[j] = (char)b;
}
input[j] = ' ';
printf("解密后：%s", input);
return 0;
}