C语言编写的维吉尼亚密码算法

#include<stdio.h>
#include<string.h>

#define SIZE 100

char key[SIZE];
char plaintext1[SIZE]={0};
int ciphertext1[SIZE]={0};

int plaintext2[SIZE]={0};
char ciphertext2[SIZE]={0};

void GetKey() {
printf("请输入密钥");
scanf("%s",key);
}

void GetPlainText(){
printf("请输入明文");
scanf("%s",plaintext1);
}

void Vige_Cipher() {
unsigned int i;
   for(i=0; i<strlen(plaintext1); i++) {
bool flag1=plaintext1[i]>='a'&&plaintext1[i]<='z';
bool flag2=plaintext1[i] >='A'&&plaintext1[i]<='Z';
if(flag1){
ciphertext1[i] = (int)plaintext1[i]-(int)'a' + (int)key[i]-(int)'a';
if(ciphertext1[i]>25) {