testing

Vigenère_Cipher/README.md

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+# Vigenère Cipher
+
+## Description
+This project implements a Vigenère cipher to demonstrate basic encryption and decryption using a keyword-based shifting approach.
+
+## Directory Structure
+- `include/`: Contains the header files.
+- `src/`: Contains the source code files (`main.c` and `vigenere_cipher.c`).
+- `obj/`: Contains the compiled object files.
+- `build/`: Contains the Makefile and the compiled binary.
+
+## How to Build
+1. Navigate to the `build` directory.
+2. Run `make` to compile the project.
+
+## How to Run
+1. After building, you will find an executable named `vigenere_cipher` in the `build` directory.
+2. Run it using `./vigenere_cipher`.
+
+## How to Clean
+- Run `make clean` in the `build` directory to remove all compiled files.

Vigenère_Cipher/build/Makefile

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+# Variables
+CC = gcc
+CFLAGS = -I../include -Wall -Wextra
+OBJDIR = ../obj
+SRCDIR = ../src
+BINDIR = ../build
+
+# Source files
+SOURCES = $(SRCDIR)/main.c $(SRCDIR)/vigenere_cipher.c
+OBJECTS = $(OBJDIR)/main.o $(OBJDIR)/vigenere_cipher.o
+
+# Build target
+TARGET = vigenere_cipher
+
+# Rules
+all: $(BINDIR)/$(TARGET)
+
+$(BINDIR)/$(TARGET): $(OBJECTS)
+	$(CC) $(OBJECTS) -o $(BINDIR)/$(TARGET)
+
+$(OBJDIR)/%.o: $(SRCDIR)/%.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+clean:
+	rm -f $(OBJDIR)/*.o $(BINDIR)/$(TARGET)
+
+.PHONY: all clean
+

Vigenère_Cipher/include/vigenere_cipher.h

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+#ifndef VIGENERE_CIPHER_H
+#define VIGENERE_CIPHER_H
+
+void encrypt(char *plaintext, const char *key);
+void decrypt(char *ciphertext, const char *key);
+
+#endif // VIGENERE_CIPHER_H

Vigenère_Cipher/src/main.c

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+#include "vigenere_cipher.h"
+#include <stdio.h>
+#include <string.h>
+
+int main() {
+    char message[256];
+    char key[256];
+
+    printf("Enter a message to encrypt: ");
+    fgets(message, sizeof(message), stdin);
+    message[strcspn(message, "\n")] = '\0'; // Remove newline character
+
+    printf("Enter the encryption key: ");
+    fgets(key, sizeof(key), stdin);
+    key[strcspn(key, "\n")] = '\0'; // Remove newline character
+
+    // Encrypt the message
+    encrypt(message, key);
+    printf("Encrypted message: %s\n", message);
+
+    // Decrypt the message
+    decrypt(message, key);
+    printf("Decrypted message: %s\n", message);
+
+    return 0;
+}

Vigenère_Cipher/src/vigenere_cipher.c

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+#include "vigenere_cipher.h"
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+
+void encrypt(char *plaintext, const char *key) {
+    int keyLen = strlen(key);
+    for (int i = 0, j = 0; plaintext[i] != '\0'; i++) {
+        if (isalpha(plaintext[i])) {
+            char base = islower(plaintext[i]) ? 'a' : 'A';
+            int shift = (tolower(key[j % keyLen]) - 'a');
+            plaintext[i] = (plaintext[i] - base + shift) % 26 + base;
+            j++;
+        }
+    }
+}
+
+void decrypt(char *ciphertext, const char *key) {
+    int keyLen = strlen(key);
+    for (int i = 0, j = 0; ciphertext[i] != '\0'; i++) {
+        if (isalpha(ciphertext[i])) {
+            char base = islower(ciphertext[i]) ? 'a' : 'A';
+            int shift = (tolower(key[j % keyLen]) - 'a');
+            ciphertext[i] = (ciphertext[i] - base - shift + 26) % 26 + base;
+            j++;
+        }
+    }
+}