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# How to convert Java Octal to Decimal

In Java, Octal value can be converted into Decimal value either by using Integer.parseInt() method or own custom code. Let's see the examples.

## 1. `Integer.parseInt()` method

The parseInt() method is a part of Integer class which converts the string into an int in accordance with the specified radix.

## Example 1:

Here, the octal string values are converted into decimal values by using the `parseInt()` method. See the example below.

``````public class StudyTonight
{
public static void main(String args[])
{
String o1 = "75";
String o2 = "-56573";
String o3 = "336";

int d1 = Integer.parseInt(o1,8);
int d2 = Integer.parseInt(o2,8);
int d3 = Integer.parseInt(o3,8);

System.out.println("Decimal value is : " +d1);
System.out.println("Decimal value is : " +d2);
System.out.println("Decimal value is : " +d3);
}
}``````

Decimal value is : 61
Decimal value is : -23931
Decimal value is : 222

## Example 2:

The octal values can be converted into decimals using custom logic. This is useful when you don't want to use any built-in method.

``````public class StudyTonight
{
public static int decimalconvt(int oct)
{
int dec = 0;
int n = 0;
while(true)
{
if(oct == 0)
{
break;
}
else
{
int tmp = oct%10;
dec += tmp*Math.pow(8, n);
oct = oct/10;
n++;
}
}
return dec;
}
public static void main(String args[])
{
System.out.println("Decimal of 101 is: " +decimalconvt(101));
System.out.println("Decimal of 1756 is: " +decimalconvt(1756));
System.out.println("Decimal of -1743 is: " +decimalconvt(-1743));
}
}``````

Decimal of 101 is: 65
Decimal of 1756 is: 1006
Decimal of -1743 is: -995

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