C++ Break and Continue

Definition: Loop control statements like break and continue allow you to alter the flow of a loop based on specific conditions. They provide a way to exit a loop prematurely or skip specific iterations without stopping the entire loop process.

Why: In any professional C++ syllabus, break and continue are treated as essential tools for optimizing code. They allow you to handle exceptions within a loop—such as stopping a search once a value is found or skipping invalid data points during a calculation.

The Two Control Keywords

While both keywords affect how a loop runs, they serve very different purposes in logic building:

Example: Skipping a Specific Number

In this example, we use the continue keyword to skip the number 3 while printing a sequence from 1 to 5:

#include <iostream>
using namespace std;

int main() {
    for (int i = 1; i <= 5; i++) {
        if (i == 3) {
            continue; // Skips the rest of the code for i=3
        }
        cout << i << endl;
    }
    // Output: 1, 2, 4, 5
    return 0;
}

Comparison Table

Key Notes

• The Break in Switch: You have already seen break in switch statements. Its job there is identical: it stops the program from "falling through" to the next case.
• Infinite Loop Safety: When using continue in a while loop, ensure that the counter variable (like i++) is updated before the continue statement. Otherwise, the program may skip the increment and get stuck in an infinite loop.
• Nested Loop Behavior: A break or continue only affects the innermost loop it is currently in. If you have a loop inside a loop, breaking the inner one will not stop the outer one.