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Stop or Skip an Iteration

Stop or Skip an Iteration

Break leaves the nearest loop, while continue skips the remainder of the current iteration.

A report can skip one roll number without ignoring later students.

Before this lesson, review Repeat Until a Condition Changes when needed.

What you’ll learn

  • Use break and continue to stop or Skip an Iteration.
  • Explain how the complete example produces 1 → 3.
  • Make the practice change and explain why the result changes or stays the same.

Follow a complete C++ example

A report can skip one roll number without ignoring later students.

Read the declarations above main before tracing its statements. Each declared name supplies the value, type or operation used later. The std:: prefix selects a name from the standard library, and cout << sends a value to the output stream.

C++17 · main.cpp · complete program

#include <iostream>

int main()  {
  for (int roll = 1; roll <= 3; ++roll)  {
    if (roll == 2)  {
      continue;
    }
    std::cout << roll << '\n';
  }
  return 0;
}

Expected output

1
3
Run in C++ compiler →

Connect the code to its result

C++17 · source used in this explanation

#include <iostream>

int main()  {
  for (int roll = 1; roll <= 3; ++roll)  {
    if (roll == 2)  {
      continue;
    }
    std::cout << roll << '\n';
  }
  return 0;
}

Expected output

1
3

Break leaves the nearest loop, while continue skips the remainder of the current iteration. A report can skip one roll number without ignoring later students.

Trace the result: Read the complete program below from its starting values to the output operations. Each std::cout statement displays the value supplied at that point; \n begins the next line. The resulting lines, in order, are 1 → 3. In this example, distinguish what the program calculates or changes from what it actually displays.

Important mistakes and boundaries

In a for loop the update follows continue. In a while loop an update located after continue is skipped and may cause endless repetition.

Change the school example

C++17 · edit this complete example

#include <iostream>

int main()  {
  for (int roll = 1; roll <= 3; ++roll)  {
    if (roll == 2)  {
      continue;
    }
    std::cout << roll << '\n';
  }
  return 0;
}

Your task: Replace continue with break. Before running your edited program, predict the new output and explain which stored value, condition or object changes. Keep the rest of the example intact.

Use the complete source repeated here; this task does not depend on remembering code from another section.

Worked answer and reasoning

Worked variation: Replace continue with break. Only roll number 1 prints.

Break leaves the nearest loop, while continue skips the remainder of the current iteration. A report can skip one roll number without ignoring later students.

In a for loop the update follows continue. In a while loop an update located after continue is skipped and may cause endless repetition.

For a baseline run, save this source as main.cpp and use clang++ -std=c++17 -Wall -Wextra -pedantic main.cpp -o school, or equivalent g++ flags. Recompile after editing so that you run the updated executable.

The source and output below belong to the edited program. Compare them with the original example to see the consequence of this single change.

C++17 · worked variation · complete program

#include <iostream>

int main()  {
  for (int roll = 1; roll <= 3; ++roll)  {
    if (roll == 2)  {
      break;
    }
    std::cout << roll << '\n';
  }
  return 0;
}

Expected output

1
Run in C++ compiler →

Check your understanding

C++17 · original program for this question

#include <iostream>

int main()  {
  for (int roll = 1; roll <= 3; ++roll)  {
    if (roll == 2)  {
      continue;
    }
    std::cout << roll << '\n';
  }
  return 0;
}
Before making the practice edit, what does the original C++17 program print?
Choose one answer. You can try again.

Answer and explanation

1 3

Break leaves the nearest loop, while continue skips the remainder of the current iteration. A report can skip one roll number without ignoring later students. In a for loop the update follows continue. In a while loop an update located after continue is skipped and may cause endless repetition.

What to remember

Break leaves the nearest loop, while continue skips the remainder of the current iteration. In a for loop the update follows continue. In a while loop an update located after continue is skipped and may cause endless repetition.

Useful connections: Repeat Until a Condition Changes, Give a Task a Name.

Language and design guidance: C++ Core Guidelines and C++ working draft. The draft describes an evolving language; these examples deliberately target C++17.

Reaching the recap and completing the quizzes are separate milestones.

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