javaistic · arghyaxcodes · Dec 3, 2021 · Dec 3, 2021 · Dec 3, 2021 · Dec 3, 2021
diff --git a/src/img/docs/wroking-of-java-statement.svg b/src/img/docs/wroking-of-java-statement.svg
diff --git a/src/navs/documentation.js b/src/navs/documentation.js
@@ -6,9 +6,7 @@ const pages = createPageList(
 )
 
 export const documentationNav = {
-  'Getting started': [
-    pages['installation'],
-  ],
+  'Getting started': [pages['installation']],
   'Java Introduction': [
     pages['introduction'],
     pages['hello-world'],
@@ -20,4 +18,5 @@ export const documentationNav = {
     pages['expressions-statements-blocks'],
     pages['comments'],
   ],
+  'Java Flow Control': [pages['if-else-statement']],
 }
diff --git a/src/pages/docs/if-else-statement.mdx b/src/pages/docs/if-else-statement.mdx
@@ -0,0 +1,300 @@
+---
+title: Java if...else Statement
+description: n this tutorial, you will learn about control flow statements using Java if and if...else statements with the help of examples.
+---
+
+import { Heading } from '@/components/Heading'
+import { TipInfo } from '@/components/Tip'
+import Link from 'next/link'
+import NextImage from 'next/image'
+
+In programming, we use the `if..else` statement to run a block of code among more than one alternatives.
+
+For example, assigning grades (A, B, C) based on the percentage obtained by a student.
+
+- if the percentage is above **90**, assign grade **A**
+- if the percentage is above **75**, assign grade **B**
+- if the percentage is above **65**, assign grade **C**
+
+## 1. Java if (if-then) Statement
+The syntax of an **if-then** statement is:
+
+```java
+if (condition) {
+  // statements
+}
+```
+Here, `condition` is a boolean expression such as `age >= 18`.
+
+- if `condition` evaluates to `true` , statements are executed
+- if `condition` evaluates to `false` , statements are skipped
+
+
+## Working of if Statement
+
+<div>
+
+<NextImage
+      className="object-cover object-center shadow-xl"
+      alt="Working of Java if statement"
+      src={require('@/img/docs/wroking-of-java-statement.svg').default}
+      width={1145}
+      height={620}
+      layout="responsive"
+      blurDataURL={require('@/img/docs/wroking-of-java-statement.svg').default}
+      placeholder="blur"
+      loading="lazy"
+      quality={100}
+    />
+
+<p align="center" className="text-base text-gray-600 font-medium">Working of Java if statement</p>
+
+</div>
+
+
+### Example 1: Java if Statement
+
+```java
+class IfStatement {
+  public static void main(String[] args) {
+
+    int number = 10;
+
+    // checks if number is less than 0
+    if (number < 0) {
+      System.out.println("The number is negative.");
+    }
+
+    System.out.println("Statement outside if block");
+  }
+}
+```
+#### Output
+
+```text
+Statement outside if block
+```
+
+In the program, `number < 0` is `false`. Hence, the code inside the parenthesis is **skipped**.
+
+<TipInfo>
+
+**Note:** If you want to learn more about about test conditions, visit [Java Relational Operators](/docs/operators#3-java-relational-operators) and [Java Logical Operators](/docs/operators#4-java-logical-operators).
+
+</TipInfo>
+
+We can also use Java Strings as the test condition.
+
+### Example 2: Java if with String
+
+```java
+class Main {
+  public static void main(String[] args) {
+    // create a string variable
+    String language = "Java";
+
+    // if statement
+    if (language == "Java") {
+      System.out.println("Best Programming Language");
+    }
+  }
+}
+```
+#### Output
+
+```text
+Best Programming Language
+```
+
+In the above example, we are comparing two strings in the `if` block.
+
+## 2. Java if...else (if-then-else) Statement
+The `if` statement executes a certain section of code if the test expression is evaluated to `true`. However, if the test expression is evaluated to `false`, it does nothing.
+
+In this case, we can use an optional `else` block. Statements inside the body of `else` block are executed if the test expression is evaluated to `false`. This is known as the **if-...else** statement in Java.
+
+The syntax of the **if...else** statement is:
+
+```java
+if (condition) {
+  // codes in if block
+}
+else {
+  // codes in else block
+}
+```
+Here, the program will do one task (codes inside if block) if the condition is true and another task (codes inside else block) if the condition is false.
+
+## How the if...else statement works?
+If the condition is true, the code inside the if block is executed, otherwise, code inside the else block is executed
+Working of Java if-else statements
+
+### Example 3: Java if...else Statement
+
+```java
+class Main {
+  public static void main(String[] args) {
+    int number = 10;
+
+    // checks if number is greater than 0
+    if (number > 0) {
+      System.out.println("The number is positive.");
+    }
+
+    // execute this block
+    // if number is not greater than 0
+    else {
+      System.out.println("The number is not positive.");
+    }
+
+    System.out.println("Statement outside if...else block");
+  }
+}
+```
+#### Output
+
+```text
+The number is positive.
+Statement outside if...else block
+```
+In the above example, we have a variable named `number`. Here, the test expression `number > 0` checks if `number` is greater than 0.
+
+Since the value of the `number` is `10`, the test expression evaluates to `true`. Hence code inside the body of `if` is executed.
+
+Now, change the value of the `number` to a negative integer. Let's say `-5`.
+
+```java
+int number = -5;
+```
+If we run the program with the new value of `number`, the output will be:
+
+```text
+The number is not positive.
+Statement outside if...else block
+```
+Here, the value of number is `-5`. So the test expression evaluates to `false`. Hence code inside the body of `else` is executed.
+
+## 3. Java if...else...if Statement
+In Java, we have an if...else...if ladder, that can be used to execute one block of code among multiple other blocks.
+
+```java
+if (condition1) {
+  // codes
+}
+else if(condition2) {
+  // codes
+}
+else if (condition3) {
+  // codes
+}
+.
+.
+else {
+  // codes
+}
+```
+Here, `if` statements are executed from the top towards the bottom. When the test condition is `true`, codes inside the body of that `if` block is executed. And, program control jumps outside the **if...else...if** ladder.
+
+If all test expressions are `false`, codes inside the body of `else` are executed.
+
+## How the if...else...if ladder works?
+
+If the first test condition if true, code inside first if block is executed, if the second condition is true, block inside second if is executed, and if all conditions are false, the else block is executed
+Working of if...else...if ladder
+
+### Example 4: Java if...else...if Statement
+
+```java
+class Main {
+  public static void main(String[] args) {
+
+    int number = 0;
+
+    // checks if number is greater than 0
+    if (number > 0) {
+      System.out.println("The number is positive.");
+    }
+
+    // checks if number is less than 0
+    else if (number < 0) {
+      System.out.println("The number is negative.");
+    }
+
+    // if both condition is false
+    else {
+      System.out.println("The number is 0.");
+    }
+  }
+}
+```
+
+#### Output
+
+```text
+The number is 0.
+```
+In the above example, we are checking whether `number` is **positive**, **negative**, or **zero**. Here, we have two condition expressions:
+
+- `number > 0` - checks if `number` is greater than `0`.
+- `number < 0` - checks if `number` is less than `0`.
+
+Here, the value of `number` is `0`. So both the conditions evaluate to `false`. Hence the statement inside the body of `else` is executed.
+
+<TipInfo>
+
+**Note:** Java provides a special operator called **ternary operator**, which is a kind of shorthand notation of **if...else...if** statement. To learn about the ternary operator, visit [Java Ternary Operator](/docs/operators#java-ternary-operator).
+
+</TipInfo>
+
+## 4. Java Nested if..else Statement
+
+In Java, it is also possible to use `if..else` statements inside an `if...else` statement. It's called the nested `if...else` statement.
+
+Here's a program to find the largest of **3** numbers using the nested `if...else` statement.
+
+### Example 5: Nested if...else Statement
+
+```java
+class Main {
+  public static void main(String[] args) {
+
+    // declaring double type variables
+    Double n1 = -1.0, n2 = 4.5, n3 = -5.3, largest;
+
+    // checks if n1 is greater than or equal to n2
+    if (n1 >= n2) {
+
+      // if...else statement inside the if block
+      // checks if n1 is greater than or equal to n3
+      if (n1 >= n3) {
+        largest = n1;
+      }
+
+      else {
+        largest = n3;
+      }
+    } else {
+
+      // if..else statement inside else block
+      // checks if n2 is greater than or equal to n3
+      if (n2 >= n3) {
+        largest = n2;
+      }
+
+      else {
+        largest = n3;
+      }
+    }
+
+    System.out.println("Largest Number: " + largest);
+  }
+}
+```
+#### Output:
+
+```text 
+Largest Number: 4.5
+```
+In the above programs, we have assigned the value of variables ourselves to make this easier.
+
+However, in real-world applications, these values may come from user input data, log files, form submission, etc.