Conditional Statements and Loops in Java

Introduction

In this post, we will discuss conditional statements and loops in the Java programming language. Conditional structures allow us to take decisions in the code. Loops allow to repeat a set of intructions for many number of times.

A conditional statement is an expression that produces a true or false result. Conditional statements allow us to check a condition and execute certain parts of code depending on whether the condition is true or false. Java provides verities of ways to handle conditional statement and execute the code part based upon the result.

We would discuss simple conditional statements.

#If else statement
#switch statement

If…else statement

Use if to specify a block of code to be executed, if a specified condition is true.Use else to specify a block of code to be executed, if the same condition is false.
if (condition) {
block of code to be executed if the condition is true
}

switch statement

switch statement can have a number of possible execution paths. Use switch to specify many alternative blocks of code to be executed.

package com.testingdcos.examplescripts;

public class SwitchExample {
  
  
      public static void main(String[] args) {

          int weekday = 3;
          switch (weekday) {
              case 1:  System.out.println("Sunday"); break;
              case 2:  System.out.println("Monday"); break;
              case 3:  System.out.println("Tuesday"); break;
              case 4:  System.out.println("Wednesday"); break;
              case 5:  System.out.println("Thursday"); break;
              case 6:  System.out.println("Friday"); break;
              case 7:  System.out.println("Saturday"); break;
              
              default: System.out.println("Not in week!! ");break;
          }
      }
  }

 

Loops

We would look into the following two loops.Loops may be used in a situation when we need to execute a block of code several times.
1.While Loop
2. For Loop

For Loop

A simple for loop is a repetition control structure that allows you to efficiently write a loop that needs to execute a specific number of times.
A for loop is useful when you know how many times a task is to be repeated.

for(initialization; boolean_expression; update)
{
//Loop statements
}

While Loop

A while loop is a control structure that allows you to repeat a task a certain number of times.

A while loop looks like:

while(boolean_expression)
{
//Loop Statements
}

The statements inside the loop executes when the condition is true. This will continue as long as the expression result is true.Interesting thing is that while loop might not ever run in some cases. When the expression is tested and the result is false, the loop body will be skipped and the first statement after the while loop will be executed.

Do..while loop

A do…while loop is similar to a while loop, except that a do…while loop is guaranteed to execute at least one time.

do
{
//Loop Statements
}
while(boolean_expression);

 

Java Tutorial on this website: https://www.testingdocs.com/java-tutorial/

For more information on Java, visit the official website :

https://www.oracle.com/in/java/

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