Exercises: Basics Warm-up

Let's Think About This For a Second

This lesson isn't new teaching content — it's a task set for practicing, hands-on, the variable, datatype, operator, if-else, loop, array, and string topics you learned in the Basic chapter. Try writing each task yourself without googling it — even if you hit errors, debugging is part of the learning process. Only after that, compare the reference solution in the code block against your own.

Exercises

Task 1: Store 5 integers in an array and use a loop to calculate the sum and average. Task 2: Read an integer age from the user and classify it with if-else as "Minor", "Adult", or "Senior" (under 18, 18-59, 60 and above). Task 3: Read a string from the user and manually count its length (character count) with a loop — don't use the .length() function. Task 4: Print only the even numbers from 1 to 50 using a for loop.

• Wrote Tasks 1-2 yourself using arrays, loops, and if-else
• Wrote Task 3 with a manual loop instead of the built-in .length()
• Ran Task 4 and checked that the even number list is correct

Example Code

#include <iostream>
#include <string>
using namespace std;

int main() {
    // Task 1: sum & average
    int nums[5] = {4, 8, 15, 16, 23};
    int sum = 0;
    for (int i = 0; i < 5; i++) sum += nums[i];
    cout << "Sum: " << sum << ", Average: " << (double)sum / 5 << "\n";

    // Task 2: age classify
    int age;
    cout << "Enter age: ";
    cin >> age;
    if (age < 18) cout << "Minor\n";
    else if (age < 60) cout << "Adult\n";
    else cout << "Senior\n";

    // Task 3: manual string length
    string text;
    cout << "Enter text: ";
    cin >> text;
    int count = 0;
    for (char c : text) count++;
    cout << "Length: " << count << "\n";

    // Task 4: even numbers 1-50
    for (int i = 1; i <= 50; i++) {
        if (i % 2 == 0) cout << i << " ";
    }
    cout << "\n";

    return 0;
}

Running Task 4 should print the even numbers from 2 4 6 8 up to 50, separated by spaces, all on one line.