prob19.c

//encryption and decreption function code and there uses
#include <stdio.h>
#include <string.h>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

void encrypt(char str[]) {
    for (int i = 0; i < strlen(str); i++) {
        str[i] = str[i] + 1;
    }
}

void decrypt(char str[]) {
    for (int i = 0; i < strlen(str); i++) {
        str[i] = str[i] - 1;
    }
}

int main() {
    char str[100], choice[10];

    printf("Enter text: ");
    scanf("%s", str);

    printf("Do you want to encrypt the text? (yes/no): ");
    scanf("%s", choice);
    if (strcmp(choice, "yes") == 0) {
        encrypt(str);
    } else {
        printf("Your text is open source.\n");
    }

    printf("Do you want to read the text? (yes/no): ");
    scanf("%s", choice);
    if (strcmp(choice, "yes") == 0) {
        printf("Text: %s\n", str);
    }

    printf("Do you want to decrypt the text? (yes/no): ");
    scanf("%s", choice);
    if (strcmp(choice, "yes") == 0) {
        decrypt(str);
        printf("Decrypted Text: %s\n", str);
    }

    return 0;
}