» » Control statements in java with examples

  • Programs in java will be executed in sequential manner means line by line execution of statements.
  • By using control statements we can control the flow of execution.
  • We have three types of control statements in java.
  1. Decision making Statements.
  2. Iteration statements.
  3. Branching statements. 




1.Decision making statements in java: 

  • In some cases we will have a situation like need to execution set of statements based on a condition
  • In this scenario we need to use decision making statements in java.
  1. if
  2. if-else
  3. if-else-if
  4. switch

Simple if

  • Based on some condition if we want to execute some set of statements then we need to use if condition in java.
  • We need to keep all the required statements inside if block .
  • If the condition is true then control executes the whole block otherwise it skips the if block of statements.

  1. if( condition ){
  2. // code
  3. }

Java example program on if control statement:

  1. package controlstatementsinjava;
  2. import java.util.Scanner;
  3.  
  4. public class ControlStatementsInjava {
  5.  
  6.     /**
  7.      * @website: www.instanceofjava.com
  8.      */
  9. public static void main(String[] args) {
  10.         
  11.   Scanner in= new Scanner(System.in);
  12.  
  13.   System.out.println("Please enter a number");
  14.   int n=in.nextInt();
  15.         
  16. if(n%2==0){
  17.    System.out.println(n+" is even number");
  18.         
  19.  }
  20.   
  21. if(n%2!=0){
  22.      System.out.println(n+" is odd number");
  23. }
  24.  
  25. }
  26. }

Output:

  1. Please enter a number
  2. 5
  3. 5 is odd number

If else condition:

  • If the condition is true then control executes the whole block otherwise it skips the if block of statements
  • if condition is false  if we need to execute another set of statement we can write another if and keep all the statements in that block.
  • instead of checking multiple times we can simply use else block .
  • More about in else statement in java

  1. if( condition ){
  2. // code
  3. }else{
  4. //code
  5. }

 if else control statement with example programs:

  1. package controlstatementsinjava;
  2. import java.util.Scanner;
  3.  
  4. public class ControlStatementsInjava {
  5.  
  6.     /**
  7.      * @website: www.instanceofjava.com
  8.      */
  9. public static void main(String[] args) {
  10.         
  11.   Scanner in= new Scanner(System.in);
  12.  
  13.   System.out.println("Please enter a number");
  14.   int n=in.nextInt();
  15.         
  16. if(n%2==0){
  17.    System.out.println(n+" is even number");
  18.         
  19.  }else{
  20.      System.out.println(n+" is odd number");
  21. }

  22.  
  23. }
  24. }

Output:

  1. Please enter a number
  2. 5
  3. 5 is odd number


if else ladder :

  • In some cases we may get requirement with multiple conditions in such cases we need to use if else ladder.(if -else-if-else if -else...)

  1. if( condition ){
  2. // code
  3. }else if{
  4. //code
  5. }else {
  6.  //code
  7. }

 if else if control statement with example programs:


  1. package controlstatementsinjava;
  2. import java.util.Scanner;
  3.  
  4. public class ControlStatementsInjava {
  5.  
  6.     /**
  7.      * @website: www.instanceofjava.com
  8.      */
  9. public static void main(String[] args) {
  10.         
  11.   Scanner in= new Scanner(System.in);
  12.  
  13.   System.out.println("Please enter your age");
  14.   int age=in.nextInt();
  15.         
  16. if(age<=18){
  17.    System.out.println("Your age is between 1-18");
  18.         
  19.  }else if ((age>=18) && (age<=35)){
  20.      System.out.println(" Your age is between 18-35");
  21. }
  22. else if ((age>=35) && (age<=50)){
  23.      System.out.println(" Your age is between 35-50");
  24. }else{
  25.  
  26.   System.out.println(" Your age is above 50");
  27.  
  28. }
  29.  
  30. }
  31. }

Output:

  1. Please enter your age
  2. 20
  3. Your age is between 18-35

control statements in java

Switch statement in java:

  • Instead if writing number of if conditions we can use single switch statement


  1. switch(value)
  2.  case n1: statements;
  3. break;
  4. case n2 : statements;
  5. break;
  6. default: statements;
  7. }

Java example program on switch statement in java:


switch statement in java

Instance Of Java

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