C# Continue Example

Continue alters control flow. It is often found in loop bodies.

It allows you to skip the execution of the rest of the iteration. It jumps immediately to the next iteration in the loop. This keyword is often useful in while-loops.

Example. This program uses the continue statement in a while-true loop. In a while-true loop, the loop continues infinitely with no termination point. We use a Sleep method call to make the program easier to watch as it executes.

WhileSleep

A random number is acquired on each iteration through the loop, using the Next method on the Random type. Then, the modulo division operator is applied to test for divisibility by 2 and 3.

RandomModulo

And: If the number is evenly divisible, the rest of the iteration is aborted. The loop restarts.

C# program that uses continue keyword

using System;
using System.Threading;

class Program
{
    static void Main()
    {
	Random random = new Random();
	while (true)
	{
	    // Get a random number.
	    int value = random.Next();
	    // If number is divisible by two, skip the rest of the iteration.
	    if ((value % 2) == 0)
	    {
		continue;
	    }
	    // If number is divisible by three, skip the rest of the iteration.
	    if ((value % 3) == 0)
	    {
		continue;
	    }
	    Console.WriteLine("Not divisible by 2 or 3: {0}", value);
	    // Pause.
	    Thread.Sleep(100);
	}
    }
}

Output

Not divisible by 2 or 3: 710081881
Not divisible by 2 or 3: 1155441983
Not divisible by 2 or 3: 1558706543
Not divisible by 2 or 3: 1531461115
Not divisible by 2 or 3: 64503937
Not divisible by 2 or 3: 498668099
Not divisible by 2 or 3: 85365569
Not divisible by 2 or 3: 184007165
Not divisible by 2 or 3: 1759735855
Not divisible by 2 or 3: 1927432795
Not divisible by 2 or 3: 648758581
Not divisible by 2 or 3: 1131091151
Not divisible by 2 or 3: 1931772589
Not divisible by 2 or 3: 283344547
Not divisible by 2 or 3: 1727688571
Not divisible by 2 or 3: 64235879
Not divisible by 2 or 3: 818135261...

The C# language is a high-level language. When it is compiled, it is flattened into a sequence of instructions. These are intermediate language opcodes. With the continue statement, branch statements are generated.

IL

In branch statements, a condition is tested. And based on whether the condition is true, the runtime jumps to another instruction in the sequence. This new location is indicated by an offset in the opcode.

Note: The continue statement could be implemented by branching to the top of the loop construct if the result of the expression is true.

True, False

Summary. The continue statement exits a single iteration of a loop. It does not terminate the enclosing loop entirely or leave the enclosing function body. Continue statements can be duplicated with carefully-placed goto statements.

So: Continue is often most useful in while or do-while loops. For-loops, with well-defined exit conditions, may not benefit as much.

Do While

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