# Java Program to Add Two Integers

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## Program to Add Two Integers

So, let’s start one by one.

### Method-1 : Using the “+” operator

We normally use the + operator to add two numbers.

Below is the implementation code.

import java.util.Scanner;
class sum
{
public static void main(String args[])
{

int sum, a, b ;
//Creating the scanner class to take input from the user
Scanner obj = new Scanner(System.in);
a = obj.nextInt();
b = obj.nextInt();
sum =  a + b;
System.out.println("The sum of "+a+" and "+b+" is = "+sum);

}
}

Output :

10
-21
The sum of 10 and -21 is = -11

### Method-2 : By the double minus operator logic :

We can use the double minus logic that we use in maths i.e.

-(- ) = +

The approach will be the same as the first method we will only replace the sum logic.

Below is the implementation code.

import java.util.Scanner;
class sum
{
public static void main(String args[] )
{

int sum, a, b ;
//Creating the scanner class to take input from the user
Scanner obj = new Scanner(System.in);
a = obj.nextInt();
b = obj.nextInt();
sum =  a - (-b);
System.out.println("The sum of "+a+" and "+b+" is = "+sum);

}
}

Output:

10
11
The sum of 10 and 11 is = 21

### Method-3 : By using the sum( ) library function

We can add using the sum( ) function which is present in Integer class inside the java.lang package.

Syntax- Integer.sum(variable_1, variable_2);
import java.lang.Integer;
class sum
{
public static void main(String args[] )
{

int sum, a = 15, b = 20 ;
//Adding both integers using the library function
sum =  Integer.sum(a,b);
System.out.println("The sum of "+a+" and "+b+" is = "+sum);

}
}


Output:

The sum of 15 and 20 is = 35

### Method-4 : By incrementing and decrementing method

To add two numbers using the incrementing/decrementing method we will be using the following approach.

Approach:

• Initialize two variables ‘a’ and ‘b’ with integer values
• Run a while loop which runs until ‘a’ is greater than zero
• Inside the loop increment ‘b’ and decrement ‘a’.
• So when ‘b’ will be incremented with 1, ‘a’ times then it will result addition of ‘a’ and ‘b’.
• Display the result

Below is the implementation code.

import java.lang.Integer;
class sum
{
public static void main(String args[] )
{

int  a = 15, b = 20 ;
System.out.print("The sum of "+a+" and "+b+" is = ");
//Adding both integers using increment and decrement operators
while(a>0)
{
//Decrementing a while incrementing b
b++;
a--;
}
System.out.print(b);
}
}

Output:

The sum of 15 and 20 is = 35

### Method-4 : Using Recursion

We can use recursion to call the function until the number becomes zero.

Recursion: When a function call itself again and again is called recursion.

Below is the implementation code.

import java.util.*;

class recursion
{
public static int addNums(int num1, int num2)
{
if (num1 > 0)
return num2;
// Recursive function call
else
return addNums((num1 & num2) << 1, num1 ^ num2);
}
public static void main(String args[])
{
int a =10, b= 15;
System.out.println("The sum of "+a+ " and "+b+" is = "+addNums(a,b));
}
}

Output:

The sum of 10 and 15 is = 35

### Method-6 : Using log and exponential functions

We can also use the log and exponential functions to find out the sum of two integers in the following approach.

Approach:

• First of all we will take two integer values
• Then we will find the exponential function using exp( ) and multiply them,
• Then we will find the log of the product and typecast it to int (we need to convert it to integer as the function returns a floaf type)
• Output the sum

Below is the implementation code.

import java.lang.Math;

class sum{
public static void main(String args[] )
{
int a = 5, b =10;
//We are finding the exponential value of two numbers
//and then multiplying them. Then finding the log of the product and
//typecasting it to integer datatype
int sum = (int)Math.log(Math.exp(a)*Math.exp(b));
System.out.print("The sum of "+a+" and "+b+" is = "+ sum);
}
}

Output:

The sum of 5 and 10 is = 15

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