Loops allow you to execute a block of code multiple times. C++ provides for, while, and do-while loops.

Use loops to traverse arrays, repeat an operation until a condition is met, or run a continuous process.

• Single loop over $N$ items: $O(N)$
• Nested loops: $O(N^2)$ or higher.

cpp Standard
// For loop - traversing an array
for (int i = 0; i < 5; i++) {
    std::cout << i << " ";
}

// While loop
int count = 0;
while (count < 5) {
    count++;
}

• Infinite loops: Condition never becomes false.
• Off-by-one errors: Starting from 1 instead of 0, or using <= instead of <.
• Forgetting to increment the loop variable inside a while loop.