Home Write a function that multiplies each element in the array "myArray" by the variable "multiplyMe". c++

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Write a function that multiplies each element in the array "myArray" by the variable "multiplyMe". c++

November 10, 2022

I’m supposed to use a function to multiply all elements of an array by 5 and print the numbers after. I don’t understand how to put the array in the function definition.

What i tried:

#include <iostream>

using namespace std;

// TODO - Write your function prototype here
int MultiplyArray(int[], int);

int main()
{
    const int SIZE = 10;
    int myArray[SIZE] = {5, 10, 15, 20, 25, 30, 35, 40, 45, 50};
    int multiplyMe = 5;

    // TODO - Add your function call here
    MultiplyArray(myArray, multiplyMe);

    // print the array
    for(int i=0; i < SIZE; i++)
    {
        cout << myArray[i] << " ";
    }
    cout << endl;

    return 0;

}

// TODO - Write your function definition here
int MultiplyArray(int myArray[10], int m) {
  for (int i = 0; i <= 10; i++) {
    myArray[i] *= m;
    }
}

The output:

 sh -c make -s
 ./main
signal: segmentation fault (core dumped)

Expected output:

25 50 75 100 125 150 175 200 225 250

>Solution :

You are very close. Simply remove the 10 from the [] in the function’s parameter type, and use < instead of <= in your function’s loop. Your loop is going out of bounds of the array (look at the loop in main(), it is using < correctly).

int MultiplyArray(int myArray[], int m) {
  for (int i = 0; i < 10; ++i) { // <--
    myArray[i] *= m;
  }
}

That being said, consider passing the array’s size as a parameter, too:

#include <iostream>

using namespace std;

// TODO - Write your function prototype here
int MultiplyArray(int[], int, int);

int main()
{
    const int SIZE = 10;
    int myArray[SIZE] = {5, 10, 15, 20, 25, 30, 35, 40, 45, 50};
    int multiplyMe = 5;

    // TODO - Add your function call here
    MultiplyArray(myArray, SIZE, multiplyMe);

    // print the array
    for(int i = 0; i < SIZE; ++i)
    {
        cout << myArray[i] << " ";
    }
    cout << endl;

    return 0;

}

// TODO - Write your function definition here
int MultiplyArray(int myArray[], int size, int m) {
  for (int i = 0; i < size; ++i) {
    myArray[i] *= m;
  }
}