Sometimes it is necessary that the block or statement must be executed at least once but if the condition is initially at a false state then the block will not be executed. So for the situation where a block of code must be executed at least once a do-while loop comes into play.
It is the same as the while loop where the loop is terminated on the basis of the test condition. The main difference is that the do-while loop checks the condition at the end of the loop which allows the do-while to execute the loop at least once.
do-while Flowchart:
The syntax for do-while loop in C++:
1 2 3 4 | do { //statements.. }while (condition); |
You should use do while loop if the code needs to be executed at least once.
Example of C++ do-while loop
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | #include <iostream> using namespace std; int main () { int i = 1; // do loop do { cout << "value of i: " << i << endl; i += 1; } while( i <= 10 ); //condition check return 0; } |
Output:
1 2 3 4 5 6 7 8 9 10 | value of i: 1 value of i: 2 value of i: 3 value of i: 4 value of i: 5 value of i: 6 value of i: 7 value of i: 8 value of i: 9 value of i: 10 |