Integer value multiplication

Projects Programming
1

Hi!
I've created four integers:

int number1 = 5;
int number2 = 10;
int number3 = 15;
int number4 = 20;

I'm going use a for-loop that goes from 2 to 5.
Inside the for-loop, the numbers must be given a new value by multiplying with the value from the for-loop (they SHOULD use the value that the for-loop creates).

E.g: When for-loop has the value 2, number1 must be multiplied by the for-loop's value 2. When the for-loop has the value 3, number2 must be multiplied by the for-loop's value 3 etc.

The new value should also be printed inside the for loop right after multiplication has been performed for each of the numbers.

Does anyone have a good example? I was looking in the Arduino.cc -> Built-In examples -> For loops with arrays, but that is not what I'm looking for.

Thanks for every reply in advance!

2

Make things simpler for yourself - put the numbers you've been given into an array.

You pretty much wrote the code right there. Try replacing the word "when" with the word "if"

3

Sure arrays is one way to code it
If you don't use arrays you have to code four different if-conditions or a switch-case-break-statement

As a starting point
Write down on a sheet of paper each iteration of your for-loop with the values that you have chosen

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4

Your description is confusing

Is this the output that you are looking for ?

2 times 5 equals 10
2 times 10 equals 20
2 times 15 equals 30
2 times 20 equals 40
3 times 5 equals 15
3 times 10 equals 30
3 times 15 equals 45
3 times 20 equals 60
4 times 5 equals 20
4 times 10 equals 40
4 times 15 equals 60
4 times 20 equals 80
5 times 5 equals 25
5 times 10 equals 50
5 times 15 equals 75
5 times 20 equals 100
5

I'm looking for an example that will give the following output:

2 times 5 equals 10 and print out 10
3 times 10 equals 30 and print out 30
4 times 15 equals 60 and print out 60
5 times 20 equals 100 and print out 100

Was this easier to understand? :smiley:

6

pseudo-code

if for-loop-variable is equal to 2
calculate for-loop-variable * number1
store result in a variable
print variable to serial monitor

if for-loop-variable is equal to 3
calculate for-loop-variable * number2
store result in a variable
print variable to serial monitor

if for-loop-variable is equal to 4
calculate for-loop-variable * number3
store result in a variable
print variable to serial monitor

if for-loop-variable is equal to 4
calculate for-loop-variable * number4
store result in a variable
print variable to serial monitor

This is still very very basic
You should at least demonstrate that you know how to:

  • code a for-loop
  • code how to store a result of a calculation in a variable
  • code how to print to the serial monitor

if you can't
Take a look into this tutorial:

Arduino Programming Course

It is easy to understand and has a good mixture between explaining important concepts and example-codes to get you going. So give it a try and report your opinion about this tutorial.

best regards Stefan

7

When is our assignment due to be handed in ?

2 Likes
8

Hello

Try this with best regards to you tutor :nerd_face:

constexpr int Inputs[] {5,10,15,20};

void setup() 
{
  Serial.begin(115200); 
  int element=2;
  for (auto Input:Inputs) Serial.println(Input*element++);
}
void loop() {}

Have a nice day and enjoy coding in C++.

9 
  for (int loopIndex = 2; loopIndex <= 5; loopIndex++)
  {
    Serial.println(number1 * loopIndex);
    Serial.println(number2 * loopIndex);
    Serial.println(number3 * loopIndex);
    Serial.println(number4 * loopIndex);
  }

or

  for (int loopIndex = 2; loopIndex <= 5; loopIndex++)
  {
    number1 = 5 * loopIndex;
    Serial.println(number1);
    number2 = 10 * loopIndex;
    Serial.println(number2);
    number3 = 15 * loopIndex;
    Serial.println(number3);
    number4 = 20 * loopIndex;
    Serial.println(number4);
  }

Or do you want the multiplications to accumulate? Like:

number1 = number1 * 2; // 10
number1 = number1 * 3; // 30
number1 = number1 * 4; // 120
number1 = number1 * 5; // 600

That would be something like:

  for (int loopIndex = 2; loopIndex <= 5; loopIndex++)
  {
    number1 *= loopIndex;
    Serial.println(number1);
    number2 *= loopIndex;
    Serial.println(number2);
    number3 *= loopIndex;
    Serial.println(number3);
    number4 *= loopIndex;
    Serial.println(number4);
  }

Note "x *= y;" is a shortcut for "x = x * y;" and saves you from entering the 'x' twice.

It would help if you showed an example of the desired output.

10

See post #5

11

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