This code implements a combination of input validation, a simple...

August 27, 2025 at 04:11 PM

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


void foo(char *s, int rot) {
    char *ptr = s;
    while(*ptr != '\0') {
        if (*ptr >= 'a' && *ptr <= 'z') {
            *ptr = (char) ('a' + (*ptr - 'a' + rot) % 26);
        } else if (*ptr >= 'A' && *ptr <= 'Z') {
            *ptr = (char) ('A' + (*ptr - 'A' + rot) % 26);
        }
        ptr++;
    }
}


int bar(char* s, int key){
    if(strlen(s) != 14 || key != 18){
        return 1;
    } else if (strcmp(s, "tdalrtsestdalr")){
        //return 98 + 108 + 105 + 116 + 122 + 98 + 97 + 109 + 97 + 98 + 108 + 105 + 116 + 122;
        return 3;
    } else {
        return 2;
    }
}

int main() {
    char *input = (char *)malloc(sizeof(char) * 100);
    if(input == NULL){
        printf("Memory allocation failed\n");
        return 1;
    }
    int key;
    

    printf("Enter text to be encoded: ");
    scanf("%99s", input);

    printf("Enter key value: ");
    scanf("%d", &key);

    int z = bar(input, key);
    if(z <= 2){
        printf("err%d\n", z);
    } else {
        printf("Congratulations! Second part of key: %s\n", input);
    }

    foo(input, key);

    printf("Ciphertext: %s\n", input);
    

    free(input);
    return 0;
}

This code implements a combination of input validation, a simple Caesar cipher, and a condition for generating output based on inputs. Below is a detailed breakdown of its functionality:

1. Header Files:

The code includes the necessary libraries:

<stdio.h>: For input/output functions.
<string.h>: To manage strings.
<stdlib.h>: For memory allocation and management.
<time.h>: (Not used in this code snippet.)

2. `foo` Function:

This function performs a Caesar cipher (a basic encryption technique) on a provided string.

It loops through each character of the string s.
If the character is a lowercase letter ('a' to 'z'):
- It shifts the letter by rot positions in the alphabet. The % 26 operation ensures the shift "wraps around" within the alphabet range if necessary.
Similarly, uppercase letters ('A' to 'Z') are shifted using the same logic.
Non-alphabetic characters are left unchanged.

For example:

Input "abc", with rot=3, becomes "def".
Input "XYZ", with rot=2, becomes "ZAB".

3. `bar` Function:

This function checks specific conditions on the string s and key key:

Condition 1: If the length of s is not 14 (strlen(s) != 14) or the key is not 18 (key != 18), it returns 1.
Condition 2: If s is not equal to "tdalrtsestdalr", it returns 3.
Otherwise, if both conditions are satisfied, it returns 2.

4. `main` Function:

The main function orchestrates the program, performing the following tasks:

Allocate Memory:
- A dynamic memory allocation is done for the input buffer, with a maximum size of 100. If allocation fails, an error message is printed, and the program exits.
User Input:
- The user is prompted to enter a text string (max 99 characters) and an integer key.
Validate Input with bar:
- The bar function is called using the user input and key. Depending on the return value of bar:
  - If bar returns 1 or 2: Print an error message ("err1" or "err2").
  - If bar returns 3: Print "Congratulations! Second part of key: <input>".
Encode Text using foo:
- The Caesar cipher is applied to the input text using the provided key. The foo function modifies the string in place.
Print Encoded Text:
- The transformed string (ciphertext) is displayed.
Free Memory:
- The dynamically allocated memory for input is freed before the program exits.

What Does the Program Do Overall?

Takes a string and a key as input from the user.
Checks if the input string has 14 characters and whether the key is 18. Based on these checks:
- Prints an error message or a "congratulations" message.
Encrypts the string using a Caesar cipher.
Prints the encrypted string (ciphertext).

Example Walkthrough:

Input:

Enter text to be encoded: helloWorld
Enter key value: 3

Output:

Validation fails because the input length is not 14 and/or the key is not 18:

err1

The input is then encrypted (Caesar cipher with rot=3):

Ciphertext: khoorZruog

Note: The program has no functionality to decrypt the ciphertext and heavily relies on the string length and key matching specific criteria to display a "congratulations" message.

Generate your own explanations

Download our vscode extension

Read other generated explanations

Built by @thebuilderjr