While and Do-While Loops
Condition-based iteration
Interview Relevant: Loop control
While and Do-While Loops
While loops repeat while a condition is true.
Difference
- while: Checks condition before each iteration
- do-while: Executes at least once, checks after
Code Examples
While and do-while loops for condition-based iteration.
cpp
1// while loop
2int count = 0;
3while (count < 5) {
4 cout << count << " "; // 0 1 2 3 4
5 count++;
6}
7
8// do-while loop (executes at least once)
9int num;
10do {
11 cout << "Enter a positive number: ";
12 cin >> num;
13} while (num <= 0);
14
15// Infinite loop with break
16while (true) {
17 string input;
18 getline(cin, input);
19 if (input == "quit") break;
20 cout << "You entered: " << input << endl;
21}
22
23// Reading until EOF
24while (cin >> num) {
25 cout << "Read: " << num << endl;
26}