Completing tasks
- C++ course
- Beginner
- Lesson 86/116
- 6 min
Learn to update task status with completeTask.
Completing tasks
Now we will write the completeTask function. It marks the task at the given index as done. Signature: void completeTask(std::vector<Task>& tasks, size_t index).
In the body, first check bounds with if (index < tasks.size()); no action on invalid index. Then mark the task done with tasks[index].done = true. Also updating listTasks to show the done status makes the app more useful.
Updating the list
Let's update the listTasks function to show the done status. Before each task we print [x] if done, [ ] if not. This lets the user see the task status at a glance.
The new body: if (tasks[i].done) { std::cout << "[x] " << tasks[i].title; } else { std::cout << "[ ] " << tasks[i].title; }. This way the list shows both status and title. This lesson asks you to update listTasks and add completeTask.
Practice completeTask and list update
Define void completeTask(std::vector<Task>& tasks, size_t index); in the body check bounds with if (index < tasks.size()) and write tasks[index].done = true;. Update listTasks: with if (tasks[i].done) print "[x] ", otherwise "[ ] ", then tasks[i].title. In main add two tasks, then call completeTask(tasks, 0) and listTasks(tasks).
Starter code
#include <iostream>
#include <string>
#include <vector>
struct Task {
std::string title;
bool done;
};
void addTask(std::vector<Task>& tasks, const std::string& title) {
Task t;
t.title = title;
t.done = false;
tasks.push_back(t);
}
void listTasks(const std::vector<Task>& tasks) {
for (size_t i = 0; i < tasks.size(); ++i) {
std::cout << i + 1 << ". " << tasks[i].title << "\n";
}
}
// Define the completeTask function
int main() {
std::vector<Task> tasks;
addTask(tasks, "Ekmek al");
addTask(tasks, "Süt al");
// Add completeTask and listTasks calls
return 0;
}Sample solution
#include <iostream>
#include <string>
#include <vector>
struct Task {
std::string title;
bool done;
};
void addTask(std::vector<Task>& tasks, const std::string& title) {
Task t;
t.title = title;
t.done = false;
tasks.push_back(t);
}
void listTasks(const std::vector<Task>& tasks) {
for (size_t i = 0; i < tasks.size(); ++i) {
if (tasks[i].done) {
std::cout << "[x] " << tasks[i].title << "\n";
} else {
std::cout << "[ ] " << tasks[i].title << "\n";
}
}
}
void completeTask(std::vector<Task>& tasks, size_t index) {
if (index < tasks.size()) {
tasks[index].done = true;
}
}
int main() {
std::vector<Task> tasks;
addTask(tasks, "Ekmek al");
addTask(tasks, "Süt al");
completeTask(tasks, 0);
listTasks(tasks);
return 0;
}Expected output
[x] Ekmek al [ ] Süt al
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 completeTask body
if (index < tasks.size()) {
tasks[index].____ = true;
}if (index < tasks.size()) {
tasks[index].done = true;
}Explanation: tasks[index].done = true; marks the task done.
2 What is tasks[0].done after completeTask(tasks, 0)?
std::vector<Task> tasks;
addTask(tasks, "Ekmek al");
completeTask(tasks, 0);
std::cout << (tasks[0].done ? "true" : "false")- false
- 0
- true Correct answer
- Error
Explanation: completeTask sets tasks[0].done = true.
3 Match each expression to its meaning
| Term | Meaning |
|---|---|
void completeTask |
Function signature |
if (index < tasks.size()) |
Bounds check |
tasks[index].done = true |
Completion |
[x] |
Done mark |