CODEWITHSUNDEEP
java
user2509848
user2509848

Reputation:

Loop through method calls with varying parameters

It seems that there should be a way to write the product() calls with a for() loop. I cannot figure out how to do it. Does anybody know of a way?

// store numbers
int[] i = { 1, 7, 2, 4, 6, 54, 25, 23, 10, 65 };

System.out.println(product(i[0]));
System.out.println(product(i[0], i[1]));
........
System.out.println(product(i[0], i[1], i[2], i[3], i[4], i[5], i[6], i[7], i[8], i[9]));

public static int product(int... num) {...}

I already have product written, I just need to call product with arguments from product(i[0]) to product(i[0], i[1], i[2]..., [9]).

Final code: 

// Calculate product of any amount of numbers
public static void main(String[] args)
{
    // create Scanner for input
    Scanner in = new Scanner(System.in);

    // store numbers
    int[] array = { 1, 7, 2, 4, 6, 14, 25, 23, 10, 35 };

    for (int j = 1 ; j <= array.length; j++) {

        // Construct a temporary array with the required subset of items
        int[] tmp = new int[j];

        // Copy from the original into the temporary
        System.arraycopy(array, 0, tmp, 0, j);

        // Make a call of product()
        System.out.println(product(tmp));

    }   // end for
}   // end method main

public static int product(int... num)
{
    // product
    int product = 1;

    // calculate product
    for(int i : num)
        product *= i;

    return product;

}   // end method product

Upvotes: 3

Views: 1260

Answers (3)

But I&#39;m Not A Wrapper Class
But I&#39;m Not A Wrapper Class

Reputation: 14296

I'd loop through and keep track of each product result, then place those values in a new array. Finally, call product method on the newly created array with all products.

int[] listOfProducts = new int[i.length];
int [] tempArray;
for(int x = 0; x<i.length; x++){
    //copy i[0] to i[x] into tempArray
    System.arraycopy(i, 0, tempArray, 0, x+1);
    listOfProducts[x] = product(tempArray);
}
System.out.println(product(listOfProducts));

Upvotes: 0

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 727137

You need to create a temporary array of ints with the required number of items, copy the sub-array of i into that temporary array, and then pass it to product like this:

for (int count = 1 ; count <= i.length() ; count++) {
    // Construct a temporary array with the required subset of items
    int[] tmp = new int[count];
    // Copy from the original into the temporary
    System.arraycopy(i, 0, tmp, 0, count);
    // Make a call of product()
    System.out.println(product(tmp));
}

Upvotes: 2

Mureinik
Mureinik

Reputation: 312404

If I understand correctly, you're looking for a way to write a product method with a variable number of arguments. This can be achieved by using the ... syntax, which will make your method take any number of arguments of the given type, and allow you to handle them as an array inside the method. E.g.:

public static int product (int... numbers) {
    int product = 1;
    for (int number : numbers) {
        product *= number;
    }
    return product;
}

Upvotes: 0

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