#include<stdio.h>
#include<string.h>
int main()
{
	char plaintext[100] = { 0 }, ciphertext[100] = { 0 };
	printf("请输入明文：");
	gets(plaintext);
	for (unsigned int i = 0; i <= strlen(plaintext); i++) {
		if (plaintext[i] >= 65 && plaintext[i] <= 90) {
			if (plaintext[i] >= 87 && plaintext[i] <= 90) {
				ciphertext[i] = plaintext[i] - 22;
			}
			else if (plaintext[i] <= 86 && plaintext[i] >= 65) {
				ciphertext[i] = plaintext[i] + 4;
			}
		}
		else if (plaintext[i] >= 97 && plaintext[i] <= 122) {
			if (plaintext[i] >= 119 && plaintext[i] <= 122) {
				ciphertext[i] = plaintext[i] - 22;
			}
			else if (plaintext[i] >= 97 && plaintext[i] <= 118) {
				ciphertext[i] = plaintext[i] + 4;
			}
		}
		else if (plaintext[i] == '#')break;
		else if (plaintext[i] >= 33 && plaintext[i] <= 64) {
			ciphertext[i]=plaintext[i];
		}
	}
	printf("密文为：%s", ciphertext);
	return 0;
}