C# Expressions, Statements and Blocks: In this tutorial, we will learn about C# expressions, C# statements, difference among expression and statements, and C# blocks.

Many times while reading a C# book or reading any article you may encounter a word named expression.. Also, you may begin considering what precisely is expression.

Expressions, statements and blocks are the building block of a C# program. We have been using them since our first “Hello World” program.


C# Expressions

An expression in C# is a combination of operands (variables, literals, strategy calls) and operators that can be assessed to a single value. To be exact, an expression should have at any rate one operand but might not have any operator.

Let’s look at the example below:

double temperature;
temperature = 42.05;

Here, 42.05 is an expression. Likewise, temperature = 42.05 is an expression as well.

int a, b, c, sum;
sum = a + b + c;

Here, a + b + c is an expression.

if (age>=18 && age<58)
	Console.WriteLine("Eligible to work");

Here, (age>=18 && age<58) is an expression that returns a boolean value. “Eligible to work” is likewise an expression.


C# Statements

A statement is a fundamental unit of execution of a program. A program comprises of different statements.

For instance:

int age = 21;
Int marks = 90;

In the above example, the two lines above are statements.

There are various types of statements in C#. In this tutorial, we’ll mainly focus on two of them:

  • Declaration Statement
  • Expression Statement

Declaration Statement

Declaration statements are used to declare and introduce variables.

For instance:

char ch;
int maxValue = 55;

Both singe ch; and int maxValue = 55; are declaration statements.


Expression Statement

An expression followed by a semicolon is called an expression statement.

For instance:

/* Assignment */
area = 3.14 * radius * radius;
/* Method call is an expression*/

System.Console.WriteLine("Hello");

Here, 3.14 * radius* radius is an expression and area= 3.14 * radius* radius; is an expression statement.

In like manner, System.Console.WriteLine(“Hello”); is both an expression and a statement.

Next to declaration and expression statement, there are:

• Selection Statements (if…else, switch)

• Iteration Statements (do, while, for, foreach)

• Jump Statements (break, continue, goto, return, yield)

• Exception Handling Statements (throw, try-catch, try-finally, try-catch-finally)

These statements will be talked about in later tutorial.

In the event that you want to learn more about statements, visit C# Statements ( C# reference)


C# Blocks

A block is a combination of zero or more statements that is enclosed inside curly brackets { }.

For instance:

Example 1: C# Blocks with statements

using System;

namespace Blocks
{
	class BlockExample
	{
		public static void Main(string[] args)
		{
			double temperature = 42.05;
			if (temperature > 32)
			{	// Start of block
				Console.WriteLine("Current temperature = {0}", temperature);
				Console.WriteLine("It's hot");
			}	// End of block
		}
	}
}

At the point when we run the program, the output will be:

Current temperature = 42.05
It's hot

Here, the two statements inside { }:

Console.WriteLine("Current temperature = {0}", temperature);

Furthermore,

Console.WriteLine("It's hot");

forms a block


Example 2: C# Blocks without statements

A block might not include any statements inside it as demonstrated in the beneath example.

using System;

namespace Blocks
{
	class BlockExample
	{
		public static void Main(string[] args)
		{
			double temperature = 42.05;
			if (temperature > 32)
			{	// Start of block
				// No statements
			}	// End of block
		}
	}
}

Here, the curly braces { } after if(temperature > 32) contains just comments and no statements.


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