Decision Making in Java Programming with Syntax and Examples

1. Objective

After completing Java String Methods an Constructors, we are moving towards Decision Making in Java. In this tutorial for Decision Making in Java, we are going to study the various decision-making Statements in Java: If Statement, If-else Statement, Nested-if Statement, If-else-if Statement, Switch Case Statement with their Syntax, uses, limitations, and examples.

So, let’s start Decision Making in java tutorial.

Decision Making in Java Programming with Syntax and Examples

Decision Making in Java Programming with Syntax and Examples

2. What is Decision Making in Java?

Decision-making statements are the same as the decision making we face in real life, in programming languages too we face situations similar to real life where we need to apply conditions to take decisions. The most commonly used loops statements in Java are

  1. If
  2. If-else
  3. Nested-if
  4. If-else-if
  5. Switch-case
  6. Jump

Do you know What are the Loops in Java?

3. Types of Decision-Making in Java

a. Java If Statement

If Statement in java is the simplest selection statement in the Java language, it checks the condition and then the loop is executed.
Syntax

if(condition)
     {
           // Statements to execute if condition is true
     }
If Statement in decision making in java

Decision Making in Java – Java If Statement

Example of If Statement in java

class IfDemo
  {
   public static void main(String args[])
     {
           int i = 10;
           if (i > 15)
           System.out.println("10 is less than 15");
// This statement will be executed  as if considers one statement by default
              System.out.println("I am Not in if");
      }
   }

Folllow this link to know about Java Datatypes.

b. If-else Statement in Java

Java if-else statement is an upgraded if statement, it tests the condition and if the condition is false then ‘else’ statement is executed. These Statements are popular among Decision Making in Java Statements.
Syntax

if (condition)
  {
    // Executes this block if condition is true
  }
    else
    {
      // Executes this block if condition is false
    }
 If-Else Statement in Decision Making in Java

Decision Making in Java – Java If-Else Statement

Example of If-else Statements in java

// Java program to illustrate if-else statement
class IfElseDemo
  {
    public static void main(String args[])
    {
 		 int i = 10;
     if (i < 15)
     System.out.println("i is smaller than 15");
    else
    System.out.println("i is greater than 15");
    }
  }

Let’s revise What is Java Character Class

c. Nested-If Statements in Java

Java nested if statement is an if statement or an if-else statement within an if statement. Java allows nesting within the loops.
Syntax

if (condition1)
  {
    // Executes when condition1 is true
    if (condition2)
    {
      // Executes when condition2 is true
    }
  }
Nested-If Statements - Decision Making in Java

Decision Making in Java – Java Nested-If Statements

To understand programming follow the links Java Class and Object

Example of Nested-If statements in java 

// Java program to illustrate nested-if statement
  class NestedIfDemo
    {
    public static void main(String args[])
      {
        int i = 10;
        if (i == 10)
          {
            // First if statement
            if (i < 15)
            System.out.println("i is smaller than 15");
            // Nested - if statement Will only be executed if statement above it is true
            if (i < 12)
            System.out.println("i is smaller than 12 too");
        else
        System.out.println("i is greater than 15");
          }
      }
  }

d. If-Else-If Ladder Statement in Java

In java if-else-if ladder, the user can use many if else statement within the loop. If one condition holds true the rest of the loops is bypassed.
Syntax 

if (condition)
statement;
else if (condition)
statement;
.
.
else
statement;
Decision Making In Java - If-Else-If Statements

Decision Making In Java – Java If-Else-If Statements

Example

// Java program to illustrate if-else-if ladder
class ifelseifDemo
  {
    public static void main(String args[])
    {
      int i = 20;
      if (i == 10)
      System.out.println("i is 10");
      else if (i == 15)
      System.out.println("i is 15");
      else if (i == 20)
      System.out.println("i is 20");
    else
    System.out.println("i is not present");
    }
  }

Do you know about Static & Instance Method in Java

e. Switch Case in Java

The switch statement provides an easy way to execute conditions to different parts of the code. In a switch statement, a default statement can also be introduced, there must be no duplicate cases too.
Syntax

switch (expression)
{
case value1:
statement1;
break;
case value2:
statement2;
break;
.
.
case valueN:
statementN;
break;
default:
statementDefault;
}

 

Decision Making In Java - Switch case Statement

Decision Making In Java – Switch case Statement

Example of Switch Case statements in java

// Java program to illustrate switch-case
class SwitchCaseDemo
  {
    public static void main(String args[])
    {
    int i = 9;
    switch (i)
      {
      case 0:
      System.out.println("i is zero.");
      break;
      case 1:
      System.out.println("i is one.");
      break;
      case 2:
      System.out.println("i is two.");
      break;
      default:
      System.out.println("i is greater than 2.");
      }
    }
  }

Read about Switch Statement in Java with Practical Example

f.  jump statements in java

Java has three jump statements; they are-
i. Break
ii. Continue
iii. Return
These statements are responsible for transferring the control to another part of the program. Before we move towards jump statements, let’s revise Java Operators

i. Break Statement in Java

Java break statement used to terminate the program, or it is also used as a form of goto statement.

  • When used for an exit
Decision Making In Java - Break Statements

Decision Making In Java – Break Statements

Example of exit statements in java

// Java program to illustrate using break to exit a loop
class BreakLoopDemo
  {
    public static void main(String args[])
    {
     // Initially loop is set to run from 0-9
     for (int i = 0; i < 10; i++)
      {
        // terminate loop when i is 5.
        if (i == 5)
        break;
        System.out.println("i: " + i);
      }
    System.out.println("Loop complete.");
    }
  }
  •  When used as goto statement

Syntax 

label:
{
statement1;
statement2;
statement3;
.
.
}

Example of Goto statements in java

// Java program to illustrate using break with goto
class BreakLabelDemo
  {
  public static void main(String args[])
    {
    boolean t = true;
    // label first
    first:
      {
      // Illegal statement here as label second is not introduced yet break second;
      second:
        {
        third:
          {
          // Before break
          System.out.println("Before the break statement");
          // break will take the control out of second label
          if (t)
          break second;
          System.out.println("This won't execute.");
          }
          System.out.println("This won't execute.");
        }
        // Third block
        System.out.println("This is after second block.");
      }
    }
  }

Let’s Discuss the String vs StringBuffer vs StringBuilder in Java

ii. Continue Statement in Java

Decision Making in java

Decision Making in java – continue Statement in Java

This statement is used to continue an iteration of a loop, i.e. to continue for a loop to run with a different condition.
Decision Making in java – continue Statement in Java
Example of continue statements in java

// Java program to illustrate using continue in an if statement
class ContinueDemo
  {
  public static void main(String args[])
    {
    for (int i = 0; i < 10; i++)
      {
      // If the number is even skip and continue
      if (i%2 == 0)
      continue;
      // If number is odd, print it
      System.out.print(i + " ");
      }
    }
  }

iii. Java Return Statement

A return statement in Java is used to return the control to a method.
Example of return statements in java

// Java program to illustrate using return
class Return
  {
  public static void main(String args[])
    {
    boolean t = true;
    System.out.println("Before the return.");
    if (t)
    return;
    // Compiler will bypass every statement after return
    System.out.println("This won't execute.");
    }
  }

So, this was all about Java Decision Making Statements. Hope you like our explanation.

4. Conclusion

In this tutorial for Decision Making in Java, we learned about the basic loops in Java, how they are iterated with their example and Syntax, this will help us understand and code better in the further tutorials. Furthermore, if you have a query, feel free to ask in the comment box

Related Topic – Java Array
For reference

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