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What are C# conditionals?

Honoura Michael

What are C# conditionals??

Introduction

Conditionals involve a program’s ability to deduce and do different things depending on the conditions of the codes written in that program.

This shot is targeted at beginners with a basic understanding of C# fundamentals.

Conditionals in C#

Below are the types of conditional statements in C#:

a. The if(condition) statement

b. The if(condition)-else statement

c. The nested if(condition)-else statement

d. The switch statement

The basis for conditionals in C#, and most programming languages, is the if statement. To make it more complex, block(s) of else and else-if statements can also be added.

The if(condition) statement

The if statement is used as a single statement where the codes in the curly {} brackets execute if, and only if, the conditions in the round () brackets are true.

// The `if` syntax

if(this expression or condition is true)
{
// execute this code;
}

The expression and condition terms refer to instructions the program uses to make decisions before executing any code.

The executable code below describes an if statement:


using System;
class Conditional
{
    static void Main()
    {
      int age = 19;
      
      //Condition
      if(age >= 13 && age <= 19) 
      //True block
      {
        Console.WriteLine("You are a teenager!");
        //This block of code will execute because the condition is true.
      }
        
    }
}
If statement.

The output will be, “You are a teenager!” because the value of the age variable is equal to 19.

The if-else statement.

The if-else statement allows for two conditions to be checked. If the conditions in the first round () brackets are true, the codes in the first curly {} brackets will execute. Otherwise, the codes in the second curly {} brackets will execute.

// The `if-else` syntax

if(this expression or condition is true)
{
// execute this statement;
}
else
{
// execute this statement;
}

The code below describes an if-else statement.


using System;
class Conditional
{
    static void Main()
    {
      int age = 7;
      
      //Condition
      if(age >= 13 && age <= 19) 
      //True block
      {
        Console.WriteLine("You are a teenager!");
        //This block of code will not execute because the condition is not met.
      }
      else
      //False/Default block
      {        
        Console.WriteLine("You are not a teenager!");
         //This block of code will execute instead.
      }
        
    }
}
If-else statement

The value of the age variable is less than 13, which sets the condition in the if block to false and the output to ‘‘You are not a teenager!’’.

The nested if-else statement.

This nested if-else statement allows for a series of conditions to be checked continuously, from top to bottom, until a condition is met. Then, the code in that block is executed.

// The nested `if-else` syntax

if(expression1 or condition1 is true)
{
// execute statement1;
}
else if(expression2 or condition2 is true)
{
// execute statement2;
}
else if(expression3 or condition3 is true)
{
// execute statement3;
} 
// You can nest as many else-ifs as you need
else
{
// execute this statement;
}


The code below describes a nested if-else statement.


using System;
class Conditional
{
    static void Main()
    {
      int age = 30;
      
      //Condition
      if(age >= 13 && age <= 19) 
      //True block1
      {
        Console.WriteLine("You are a teenager!");
        //This block of code will not execute because the condition is not met.
      }
      else if(age == 20)
      //True block2
      {        
        Console.WriteLine("Are you a college graduate?");
        //This block of code will not execute because the condition is not met.
      }
      else if(age == 30)
      //True block3
      {        
        Console.WriteLine("What is your net worth?");
        //This block of code will execute because the condition is met.
      }
      else
     //False/Default block
      {        
        Console.WriteLine("You are not a teenager!");
         //This block of code will not execute because there is a valid condition above it.
      }
        
    }
}
Nest if-else statement

The execution of this code will check the if condition first. If the check is true, the statement will be displayed. If the check is false, the first else-if is checked.

If it is true, then the statements in that else-if block are executed; otherwise, the check will go to next else-if part and continue until one of the conditions return true.

If the results of all the conditions are false, the check will go to the else part and execute it.

The switch statement.

A switch statement in C# checks the value of a variable against multiple cases. If it matches any case, the statements in that case will execute and the break keyword will stop the switch.

Each case in a block of switch cases holds an option called an ‘identifier’. When a value is entered, it is compared with the cases in the switch block until an exact match is found.

If a match is not found, the default statement is executed.

// The `switch` syntax

switch(variable or value) {
   case expression1:
      statement(s)1;
      break;
   case expression2:
    statement(s)2;
      break;
   case expression3:
      statement(s)3;
      break;
     //you can add as many cases as is needed
   default:
   statement(s)default;
    break;
}

The code below describes a switch statement.


using System;
class Conditional
{
    static void Main()
    {
      string city = Benue;    
      
      switch(city) 
      {
        //False case
      case "Lagos":
        Console.WriteLine($"Welcome to {city}, Nigeria!");
        //This block of code will not execute because the condition is not met.
        break;
             
        //Another false case
      case "Abuja":
        Console.WriteLine($"Welcome to {city}, Nigeria!");
        //This block of code will not execute because the condition is not met.
        break;
      
         //True case
      case "Benue":
        Console.WriteLine($"Welcome to {city}, Nigeria!");
         //This block of code will execute because the condition is met.
        break;
      
      //Default case
      default:
        Console.WriteLine($"Welcome to Nigeria!");
         //This block of code will execute if all cases do not match the switch.
        break;            
      }
        
    }
}

Here, the variable’s value is compared to all cases in the switch block. Since it matches the third case, the statement in that case will be executed and displayed on the console.

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