Add blogpost - convert double to int in java

Author: gauravkukade

_posts/java-basic/2021-03-02-convert-double-to-int.md

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+---
+layout: post
+title: "How To Convert double To int In Java?"
+author: gaurav
+image: assets/images/2021-03-02/double-to-int-in-java.webp
+categories: [ Java, Core Java, String]
+description: "In this article you are going to learn how can we convert a double value to an integer value."
+---
+
+
+In this article, we will see how we can convert a double to an int.
+
+In java programming, you will have a double primitive value (ex 82.14), but to do the further operations you need an int value (ex. 82) so let's see how to convert double to int in java.
+
+There are three ways you can convert double to int. I will list them all below and, then we will see them one by one.
+
+1. convert double to int - using typecasting
+2. convert double to int - using `Math.round()`
+3. convert double to int - using `Double.IntValue()`
+
+> You may like to visit:
+> [How To Convert An Integer To String In Java](https://coderolls.com/convert-int-to-string/)
+
+## 1. convert double to int - using typecasting
+
+We know  `double` is a 64-bit primitive value, and int is a 32-bit primitive value. So, to convert double to int, we can downcast the double value to int.
+
+I have given a simple example below that shows to convert double to int using typecasting.
+
+```java
+/**
+ * A java program to convert double to int using typecasting 
+ * @author Gaurav Kukade at coderolls.com
+ **/
+public class DoubleToIntUsingTypecasting{
+
+     public static void main(String []args){
+        
+        double doubleValue = 82.14; // 82.14
+        
+        System.out.println("doubleValue: "+doubleValue);
+        
+        //typecase double to int
+        int intValue = (int) doubleValue; // 82
+        
+        System.out.println("intValue: "+intValue);
+     }
+}
+```
+Output:
+```java
+doubleValue: 82.14
+intValue: 82
+```
+
+The problem with the typecasting is that it will truncate the value after the decimal point. It will not round it.
+
+In the case of 82.14, we will get an int value of 82, which looks ok. But when we have a double value like 82.99, we will get only 82 and loss the 0.99 that is ~1.
+
+It may create an issue in your calculations.
+
+In the case of 82.99, it should be rounded to 83 and then converted to int.
+
+It is not possible with typecasting, but our next solution can achieve it.
+
+## 2. convert double to int  - using `Math.round()`
+
+`Math.round()` method will round the floating-point value to the nearest long value. Then we can typecast it to the int.
+
+I have given a simple java program below that shows how to convert double to int using the `Math.round()` method.
+
+```java
+/** 
+ * A java program to convert double to int using 
+ * Math.round() method 
+ * @author Gaurav Kukade at coderolls.com
+ **/
+public class DoubleToIntUsingRoundMethod{
+
+     public static void main(String []args){
+        
+        // case 1
+        double doubleValue = 82.14; // 82.14
+        
+        System.out.println("doubleValue: "+doubleValue);
+        
+        //typecase double to int
+        int intValue = (int) Math.round(doubleValue); // 82
+        
+        System.out.println("intValue: "+intValue);
+        
+        System.out.println();
+        
+        // case 2
+        double nextDoubleValue = 82.99; // 
+
+        
+        System.out.println("nextDoubleValue: "+nextDoubleValue);
+        
+        // Math.round(nextDoubleValue) returns long value
+        //typecase long to int
+        int nextIntValue = (int) Math.round(nextDoubleValue); // 83
+        
+        System.out.println("nextIntValue: "+nextIntValue);              
+     }
+}
+```
+Output:
+
+```java
+doubleValue: 82.14
+intValue: 82
+
+nextDoubleValue: 82.99
+nextIntValue: 83
+```
+## 3. convert double to int - using `Double.intValue()`
+
+
+In this way, we will convert the double primitive value to the `Double` wrapper class, and then we can use the `intValue()` method of the `Double` wrapper class.
+
+This method does not round the value before converting it to the int value. It will remove the digits after the decimal point.
+
+I have given a simple java program below that shows how to convert double to int using the `Double.IntValue()` method.
+
+```java
+/**
+ * 
+ * A java program to convert double to int using 
+ * Double.intValue() method  
+ * @author Gaurav Kukade at coderolls.com
+ * 
+ **/
+public class DoubleToIntUsingIntValueMethod{
+
+     public static void main(String []args){
+
+        double doubleValue = 82.14; // 82.14
+        
+        System.out.println("doubleValue: "+doubleValue);
+        
+        //create Double wrapper object
+        Double doubleValueObject = new Double(doubleValue);
+        
+        
+        //typecase double to int
+        int intValue = doubleValueObject.intValue(); // 82
+        
+        System.out.println("intValue: "+intValue);
+     }
+}
+```
+
+Output:
+```java
+doubleValue: 82.14
+intValue: 82
+```
+## Conclusion
+
+We can convert double to int in java using the three ways given below.
+
+**1. convert double to int - using typecasting**
+
+In this method we typecast the double value to int as give below,
+```java
+int intValue = (int) Math.round(doubleValue);
+```
+But in this way, we will lose the value after the decimal point. It will not do the rounding before converting double to int.
+   
+**2. convert double to int - using `Math.round()`**
+
+
+In this way, we use the `Math.round()` method for the rounding purpose. 
+
+`Math.round()` method round the double value to the nearest long, and then we can typecast long to the int as given below.
+```java
+int nextIntValue = (int) Math.round(nextDoubleValue);
+```
+**3. convert double to int - using `Double.IntValue()`**
+
+In this way, we convert the `double` value to the `Double` wrapper class, and then we use the `Double.intValue()` method to get the int value.
+
+```java
+//create Double wrapper object
+Double doubleValueObject = new Double(doubleValue);
+        
+//typecase double to int
+int intValue = doubleValueObject.intValue(); 
+```
+In this way also we will lose the digits after the decimal points.
+
+So this is how we do convert a double to int in java. You can check all three ([DoubleToIntUsingTypecasting.java](https://github.com/coderolls/blogpost-coding-examples/blob/main/java-basic/DoubleToIntUsingTypecasting.java), [DoubleToIntUsingRoundMethod.java](https://github.com/coderolls/blogpost-coding-examples/blob/main/java-basic/DoubleToIntUsingRoundMethod.java), [DoubleToIntUsingIntValueMethod.java](https://github.com/coderolls/blogpost-coding-examples/blob/main/java-basic/DoubleToIntUsingIntValueMethod.java)) programs on GitHub 
+
+You can read more about [string to int](https://coderolls.com/convert-int-to-string/) and [int to string](https://coderolls.com/convert-string-to-int/) conversion.
+
+-------
+You can visit my [YouTube channel 'coderolls'](https://www.youtube.com/channel/UCl31HHUdQbSHOQfc9L-wo3w?view_as=subscriber?sub_confirmation=1) to find more video tutorials.
+
+If you found this article worth, support me by  [giving a cup of Coffee ☕](https://www.paypal.me/GauravKukade)
+
+### Related Articles
+
+- [How To Convert An Integer To String In Java](https://coderolls.com/convert-int-to-string/)
+
+- [How to convert String to Integer in Java](https://coderolls.com/convert-string-to-int/)
+
+- [How To Convert StringBuilder To String In Java?](https://coderolls.com/convert-stringbuilder-to-string-in-java/)
+
+- [How Do I Compare Strings In Java](https://coderolls.com/compare-strings-in-java/)
+
+-  [How To Reverse A String In Java (5 ways)](https://coderolls.com/reverse-a-string-in-java/)
+
+
+
+