In c#, While loop is used to execute a block of statements until the specified expression return as a true.
In previous section, we learned about for loop in c# with examples. Generally, the for loop is useful when we are sure about how many times we need to execute the block of statements. In case, if we are unknown about the number of times to execute the block of statements, then while loop is the best solution.
Generally, while keyword is used to create a while loop in c# applications. Following is the syntax of defining a while loop in c# programming language to execute the block of statements till the defined condition evaluates as false.
while (boolean_expression) {
// Statements to Execute
}
If you observe above syntax, we used a while keyword to define a while loop and it contains parameter called boolean_expression.
Here if boolean_expression returns true, then the statements inside of while loop will be executed. After executing the statements, again the boolean_expression will be evaluated to execute the statements within the while loop.
In case, the boolean_expression is evaluated to false, then the while loop stops execution of statements and the program comes out of the loop.
Following is the pictorial representation of while loop process flow in c# programming language.
Now we will see how to use while loop in c# programming language with examples.
Following is the example of using while loop in c# programming language to execute the block of statements based on our requirements.
using System;
namespace Tutlane
{
class Program
{
static void Main(string[] args)
{
int i = 1;
while (i <= 4)
{
Console.WriteLine("i value: {0}", i);
i++;
}
Console.WriteLine("Press Enter Key to Exit..");
Console.ReadLine();
}
}
}
If you observe above example, we are executing the statements within the while loop by checking the condition (i <= 4) and increasing the variable i (i++) value to 1 by using increment operator.
When we execute above c# program, we will get the result like as shown below.
If you observe above result, while loop has executed till it matches the defined condition (i <= 4) and the program came out of the loop whenever the defined condition returns false.
In c#, we can use one while loop within another while loop to implement applications based on our requirements.
Following is the example of implementing nested while loop in c# programming language.
using System;
namespace Tutlane
{
class Program
{
static void Main(string[] args)
{
int i = 1;
while (i < 4)
{
Console.WriteLine("i value: {0}", i);
i++;
int j = 1;
while (j < 2) {
Console.WriteLine("j value: {0}", j);
j++;
}
}
Console.WriteLine("Press Enter Key to Exit..");
Console.ReadLine();
}
}
}
If you observe above example, we used one while loop within another while loop to achieve nested while loop functionality in our application based on our requirements.
When we execute above c# program, we will get the result like as shown below.
If you observe above example both while loops got executed and returned the result based on our requirements.
In c#, we can exit or terminate the execution of while loop immediately by using break keyword.
Following is the example of using break keyword in while loop to terminate execution of loop in c# programming language.
using System;
namespace Tutlane
{
class Program
{
static void Main(string[] args)
{
int i = 1;
while (i < 4)
{
Console.WriteLine("i value: {0}", i);
i++;
if (i == 2)
break;
}
Console.WriteLine("Press Enter Key to Exit..");
Console.ReadLine();
}
}
}
If you observe above example, whenever the variable (i) value become 2 we are terminating the loop using break statement.
When we execute above c# program, we will get the result like as shown below.
This is how we can use break statement with while loop to terminate the execution of loop based on our requirements.