CODEWITHSUNDEEP
javamethodsparameterserror-handlingvoid
mrkrebs
mrkrebs

Reputation: 11

using a void method with two int parameters instead of an int?

I have no problem using a method int to run this program; however I wanted to be able to learn how to do the void method.

I know the return statement isn't necessary in void, and for void with two int parameters. In my book it said parameters should be written as (int a, int b).

However, in my code for lines 16 and 17 

sum = computeSum(num1, num2);
product = computeProduct(num1, num2);)

I get the error incompatible types, void cannot be converted to int.

How do I rectify this for future reference? Thanks so much!

 import java.util.Scanner;

 public class Lab6
 {
     public static void main (String [] args)
     {      
         //create a scanner object for receiving user input
         Scanner keyboard = new Scanner (System.in);
         int num1, num2, sum, product;

         System.out.println ("Please enter an integer: ");
         num1 = keyboard.nextInt();
         System.out.println ("Please enter another integer: ");
         num2 = keyboard.nextInt(); 

         sum = computeSum(num1, num2);
         product = computeProduct(num1, num2);
     }

     public static void computeSum(int num1, int num2)
     {
         int sum = 0;
         sum = num1 + num2; 

         System.out.println ("The sum of your integers is " + sum);
     }

     public static void computeProduct(int num1, int num2)
     {
         int product = 0; 
         product = num1 * num2;

         System.out.println("\nThe product of your integers is: " + product);
     }
 }

Upvotes: 0

Views: 2497

Answers (3)

NevilleDNZ
NevilleDNZ

Reputation: 1279

Steve Bourne proposed that Algol68's VOID be defined as MODE VOID = STRUCT(). When Steve arrived at Bell Labs he talked Dennis into adding void as a type in C. It saved the instruction loading register for return value. Also when Steve got to the lab C types were like PL/1 namely offsets from any base you liked. They changed to A68 types but be the specific reason for this change is now lost. A few other A68isms ended up in C. Speculation: Std C could have considered typedef struct{}void ...

Upvotes: 1

MadProgrammer
MadProgrammer

Reputation: 347194

As you said, void methods don't return a value, so sum = computeSum(num1, num2); makes no sense, as computeSum doesn't return anything.

You should try using...

computeSum(num1, num2);
computeProduct(num1, num2);

instead...

Upvotes: 1

Eng.Fouad
Eng.Fouad

Reputation: 117589

The method computeSum()'s return type is void, i.e. it returns nothing which means it cannot be assigned to a variable. Hence, the following is not possible:

sum = computeSum(num1, num2);

Upvotes: 2

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