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Control Flow

Break and Continue

Loop control statements

Interview: Flow control in loops

Break and Continue

Break and continue alter loop execution flow. break immediately exits the innermost enclosing loop or switch. continue skips the rest of the current loop body and proceeds to the next iteration.

Nested Loop Break

A key limitation: break only exits the innermost loop. Breaking out of multiple nested loops requires flags, goto (rare), or refactoring into a function that returns.

Interview Corner

Q: How do you break out of nested loops in C++?

A: Three approaches: (1) Use a boolean flag set in the inner loop, checked by the outer loop. (2) Refactor the nested loops into a function and use return. (3) Use goto with a label after the outer loop — acceptable in performance-critical code when clarity is maintained. The function approach is cleanest.

Common Pitfalls

  • Break in switch inside loop: A break inside a switch-case nested in a loop exits the switch, not the loop. Use a flag variable to signal the loop to exit.
  • Overusing continue: Excessive use of continue can make logic flow difficult to follow. Consider early-exit guard clauses or restructuring the condition.

Best Practices

  • Use continue for guard clauses at the start of a loop body to skip invalid elements early, reducing nesting depth.
  • Prefer extracting nested loop logic into a named function over using goto for breaking multiple levels.