#include <stdio.h>
#include <stdlib.h>

int main(){
    system("chcp 1251");
    int UserOption = 0, EncryptKey = 0;
    char Message[140];
    printf("Choose one of the following options:\n0 - to encrypt\n1 - to decrypt\n");
    scanf("%d", &UserOption);
    if(UserOption == 0){
        printf("Enter encryption key\n");
        scanf("%d", &EncryptKey);
        printf("\nEnter your message:\n");
//      scanf("%s", &Message);
        getc(stdin);
        gets(Message);
        int i = 0;
        for(i = 0;(i < 140 && Message[i] != '\0');i++){
            Message[i] = Message[i] + EncryptKey;
            }
        printf("Encrypted message:\n");
//      for(i = 0;(i < 140 && Message[i] != '\0');i++){
//          Message[i] = Message[i] + EncryptKey;
//  }
            printf("%s\n", Message);

    }
    if(UserOption == 1){
        printf("Enter encryption key\n");
        scanf("%d", &EncryptKey);
        printf("Enter encrypted message\n");
        getc(stdin);
        gets(Message);
        int i = 0;
        for(i = 0;i < 140 && Message[i] != '\0';i++){
//          scanf("%s", &Message[i]);
            Message[i] = Message[i] - EncryptKey;
        }
        printf("Decrypted message:\n");
        printf("%s\n", Message);
    }
    system("pause");
    return 0;
}