C# - do while Loop

The do while loop is the same as while loop except that it executes the code block at least once.

Syntax:
do
{
    //code block


} while(condition);

The do-while loop starts with the do keyword followed by a code block and a boolean expression with the while keyword. The do while loop stops execution exits when a boolean condition evaluates to false. Because the while(condition) specified at the end of the block, it certainly executes the code block at least once.

Example: do-while Loop
int i = 0;

do
{
    Console.WriteLine("i = {0}", i);
    i++;

} while (i < 5);
Output:
i = 0
i = 1
i = 2
i = 3
i = 4

Specify initialization out of the loop and increment/decrement counter inside do while loop.

Use break or return to exit from the do while loop.

Example: Exit from the do-while Loop
int i = 0;

do
{
    Console.WriteLine("i = {0}", i);
    i++;
    
    if (i > 5)
        break;

} while (i < 10);
Output:
i = 0
i = 1
i = 2
i = 3
i = 4
i = 5

Nested do-while

The do-while loop can be used inside another do-while loop.

Example: Nested do-while Loop
int i = 0;

do
{
    Console.WriteLine("Value of i: {0}", i);
    int j = i;

    i++;
                
    do
    {
        Console.WriteLine("Value of j: {0}", j);
        j++;
    } while (j < 2);

} while (i < 2);
Output:
i = 0
j = 0
j = 1
i = 1
j = 1
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