Create the Simple To Do List in C Language with free codes

Index

Introduction

Here we are going to create a simple To Do List in C Language which allow to user to create, read, update, and delete the tasks from the to-do items.

Pattern for Creating To Do List

The Pattern of the logic of the To Do List is based on managing arrays of structures “ToDoItem”. Each structure holds task string and a completion status. Basic Operation such as add, update, delete, and mark as completed are performed using array manipulations and string operations.

Project Codes

Here is the complete Project code of To Do List in C,

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

#define MAX_TODOS 100
#define MAX_LEN 100

typedef struct {
    char task[MAX_LEN];
    int completed;
} Todo;

void addTodo(Todo todos[], int *count) {
    if (*count >= MAX_TODOS) {
        printf("To-do list is full.\n");
        return;
    }

    printf("Enter the task: ");
    getchar(); // To consume the newline character left by the previous input
    fgets(todos[*count].task, MAX_LEN, stdin);
    todos[*count].task[strcspn(todos[*count].task, "\n")] = '\0'; // Remove the newline character
    todos[*count].completed = 0;
    (*count)++;
    printf("Task added.\n");
}

void displayTodos(Todo todos[], int count) {
    if (count == 0) {
        printf("No tasks in the to-do list.\n");
        return;
    }

    printf("To-Do List:\n");
    for (int i = 0; i < count; i++) {
        printf("%d. %s [%s]\n", i + 1, todos[i].task, todos[i].completed ? "Completed" : "Not Completed");
    }
}

void updateTodo(Todo todos[], int count) {
    int index;
    printf("Enter the task number to update: ");
    scanf("%d", &index);

    if (index < 1 || index > count) {
        printf("Invalid task number.\n");
        return;
    }

    printf("Enter the new task: ");
    getchar(); // To consume the newline character left by the previous input
    fgets(todos[index - 1].task, MAX_LEN, stdin);
    todos[index - 1].task[strcspn(todos[index - 1].task, "\n")] = '\0'; // Remove the newline character
    printf("Task updated.\n");
}

void deleteTodo(Todo todos[], int *count) {
    int index;
    printf("Enter the task number to delete: ");
    scanf("%d", &index);

    if (index < 1 || index > *count) {
        printf("Invalid task number.\n");
        return;
    }

    for (int i = index - 1; i < *count - 1; i++) {
        todos[i] = todos[i + 1];
    }
    (*count)--;
    printf("Task deleted.\n");
}

void markComplete(Todo todos[], int count) {
    int index;
    printf("Enter the task number to mark as completed: ");
    scanf("%d", &index);

    if (index < 1 || index > count) {
        printf("Invalid task number.\n");
        return;
    }

    todos[index - 1].completed = 1;
    printf("Task marked as completed.\n");
}

int main() {
    Todo todos[MAX_TODOS];
    int count = 0;
    int choice;

    while (1) {
        printf("\nTo-Do List Menu:\n");
        printf("1. Add Task\n");
        printf("2. Display Tasks\n");
        printf("3. Update Task\n");
        printf("4. Delete Task\n");
        printf("5. Mark Task as Completed\n");
        printf("6. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);

        switch (choice) {
            case 1:
                addTodo(todos, &count);
                break;
            case 2:
                displayTodos(todos, count);
                break;
            case 3:
                updateTodo(todos, count);
                break;
            case 4:
                deleteTodo(todos, &count);
                break;
            case 5:
                markComplete(todos, count);
                break;
            case 6:
                printf("Exiting program.\n");
                return 0;
            default:
                printf("Invalid choice. Please try again.\n");
        }
    }
}