# Currying Functions in Java with Examples

#### Currying Functions in Java with Examples

Function Currying is a concept of breaking a function with many arguments into many functions with single argument in such a way, that the output is same. In other words, its a technique of simplifying a multi-valued argument function into single-valued argument multi-functions.

Consider the example to clear the concept:

Currying breaks down higher order functions into a series of smaller cascaded functions which take in one argument and return a function except for the last cascaded function which returns the desired value.

For example:

Let there be a function which maps as
f:(u, v) -> w

Currying the above function will produce
g:(u->(v->w))

Thus g maps from u to a function which in turn maps from v to w
The above mathematical expression can also be represented as:
{g(u)}(v)=f(u, v)

Hence, curry(f) = g

Below are some examples in Java to demonstrate Function Currying:

Example 1: Adding 2 numbers using Function Currying

// Java Program to demonstrate Function Currying

import java.util.function.Function;

public class P_AI {
public static void main(String args[])
{

// Using Java 8 Functions
// to create lambda expressions for functions
// and with this, applying Function Currying

// Curried Function for Adding u & v
Function<Integer,
Function<Integer, Integer> >
curryAdder = u -> v -> u + v;

// Calling the curried functions

// Calling Curried Function for Adding u & v
.apply(2)
.apply(3));

}
}
Output:
Example 2: Multiplying 2 numbers using Function Currying

// Java Program to demonstrate Function Currying

import java.util.function.Function;

public class P_AI {
public static void main(String args[])
{

// Using Java 8 Functions
// to create lambda expressions for functions
// and with this, applying Function Currying

// Curried Function for Multiplying u & v
Function<Integer,
Function<Integer, Integer> >
curryMulti = u -> v -> u * v;

// Calling the curried functions

// Calling Curried Function for Multiplying u & v
System.out.println("Multiply 2, 3 :"
+ curryMulti
.apply(2)
.apply(3));
}
}
Output:
Multiply 2, 3 :6
Example 3: Adding 3 numbers using Function Currying

// Java Program to demonstrate Function Currying

import java.util.function.Function;

public class P_AI {
public static void main(String args[])
{

// Using Java 8 Functions
// to create lambda expressions for functions
// and with this, applying Function Currying

// Curried Function for Adding u, v & w
Function<Integer,
Function<Integer,
Function<Integer, Integer> > >
triadder = u -> w -> v -> u + w + v;

// Calling the curried functions

// Calling Curried Function for Adding u, v & w