Passing an Array to a Function in Java

Passing an array to a function is an easy-to-understand task in Java. In this article, we will check how to pass an array as a method parameter.

Caller Function Vs Called Function

Let function GFG() be called from another function GFGNews(). Here, GFGNews is called the “Caller Function” and GFG is called the “Called Function OR Callee Function”. The arguments/parameters which GFGNews passes to GFG are called "Actual Parameters" and the parameters in GFG are called "Formal Parameters".

The array to pass can be a one-dimensional(1D) array or a multi-dimensional array such as a 2D or 3D array.

Syntax to Pass an Array as a Parameter

1. Caller Function

called_function_name(array_name);

The code for the called function depends on the dimensions of the array. The number of square brackets in the function prototype is equal to the dimensions of the array, i.e. [n] for 1D arrays, [n][n] for 2D arrays, [n][n][n] for 3D arrays, and so on.

2. Called Function

One Dimensional Array

returnType functionName(datatype[] arrayName) {
//statements
}

Two Dimensional Array

returnType functionName(datatype[][] arrayName) {
//statements
}

Here:

• returnType: the return type of the called function
• functionName: name of the called function
• datatype: the datatype of the array
• arrayName: name of the array

Note: We can also write the function in the similar way for 1 and 2 Dimensional mentioned below.

returnType functionName (datatype arrayName[])
returnType functionName (datatype arrayName[][])

Example to Pass an Array to a Function

// Java Program to Pass an Array to a Function
import java.io.*;

class GFG {
      
  	void function1(int[] a) {
        System.out.println("The first element is: " + a[0]);
    }
  	
    void function2(int[][] a) {
        System.out.println("The first element is: " + a[0][0]);
    }

    public static void main(String[] args) {
     
        GFG obj = new GFG();

        int[] arr1 = { 1, 2, 3, 4, 5 };
      
        int[][] arr2 = { { 10, 20, 30 },
                         { 40, 50, 60 },
                         { 70, 80, 90 } };
      
        // passing the 1D array to function 1
        obj.function1(arr1);
      
        // passing the 2D array to function 2
        obj.function2(arr2);
    }
}

The first element is: 1
The first element is: 10