## C++ || Simple Math Using Integer & Double

This page will display the use of int and double data types.

**==== ADDING TWO NUMBERS TOGETHER ==== **

To add two numbers together, you will have to first declare your variables by doing something like this.

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// ============================================================================// Author: Kenneth Perkins// Date: Jan 4, 2012// Updated: Feb 15, 2021// Taken From: http://programmingnotes.org/// File: addition.cpp// Description: Demonstrates adding numbers together// ============================================================================#include <iostream>int main(){ int num1 = 0; int num2 = 0; int sum = 0; std::cout << "Please enter the first number: "; std::cin >> num1; std::cout << "\nPlease enter the second number: "; std::cin >> num2; // calculate the sum of the two numbers here sum = num1 + num2; std::cout << "\nThe sum of " <<num1<<" and "<<num2<< " is: "<< sum; return 0;}// http://programmingnotes.org/

Notice in lines 12-14, I declared my variables, giving them a name. You can name your variables anything you want, with a rule of thumb as naming them something meaningful to your code (i.e avoid giving your variables arbitrary names like “x” or “y”). In line 22 the actual math process is taking place, storing the sum of “num1” and “num2” in a variable called “sum.” I also initialized my variables to zero. You should always initialize your variables.

The above code should give you the following output:

`Please enter the first number: 8`

Please enter the second number: 24

The sum of 8 and 24 is: 32

**==== SUBTRACTING TWO NUMBERS ==== **

Subtracting two numbers works the same way as the above code, and we would only need to edit the above code in one place to achieve that. In line 22, replace the addition symbol with a subtraction sign, and you should have something like this:

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// ============================================================================// Author: Kenneth Perkins// Date: Jan 4, 2012// Updated: Feb 15, 2021// Taken From: http://programmingnotes.org/// File: subtraction.cpp// Description: Demonstrates subtracting numbers together// ============================================================================#include <iostream>int main(){ int num1 = 0; int num2 = 0; int sum = 0; std::cout << "Please enter the first number: "; std::cin >> num1; std::cout << "\nPlease enter the second number: "; std::cin >> num2; // calculate the difference of the two numbers here sum = num1 - num2; std::cout << "\nThe difference between " <<num1<<" and "<<num2<< " is: "<< sum; return 0;}// http://programmingnotes.org/

The above code should give you the following output:

`Please enter the first number: 8`

Please enter the second number: 24

The difference between 8 and 24 is: -16

**==== MULTIPLYING TWO NUMBERS ==== **

This can be achieved the same way as the 2 previous methods, simply by editing line 22, and replacing the designated math operator with the star symbol “*”.

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// ============================================================================// Author: Kenneth Perkins// Date: Jan 4, 2012// Updated: Feb 15, 2021// Taken From: http://programmingnotes.org/// File: multiplication.cpp// Description: Demonstrates multiplying numbers together// ============================================================================#include <iostream>int main(){ int num1 = 0; int num2 = 0; int sum = 0; std::cout << "Please enter the first number: "; std::cin >> num1; std::cout << "\nPlease enter the second number: "; std::cin >> num2; // calculate the product of the two numbers here sum = num1 * num2; std::cout << "\nThe product of " <<num1<<" and "<<num2<< " is: "<< sum; return 0;}// http://programmingnotes.org/

The above code should give you the following output:

`Please enter the first number: 8`

Please enter the second number: 24

The product of 8 and 24 is: 192

**==== DIVIDING TWO NUMBERS TOGETHER ==== **

This one is a little different from the other three. Before we would use integer variables to store our data. In division, when you divide numbers together, sometimes they end in decimals. Integer data types can not store decimal data (try it yourself and see), so here is where we use a floating point data type to store the values.

So the resulting code will basically be the same as the other previous three, only instead of our variables being of type int, they will be of type double.

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// ============================================================================// Author: Kenneth Perkins// Date: Jan 4, 2012// Updated: Feb 15, 2021// Taken From: http://programmingnotes.org/// File: division.cpp// Description: Demonstrates dividing numbers together// ============================================================================#include <iostream>int main(){ int num1 = 0; int num2 = 0; double sum = 0; std::cout << "Please enter the first number: "; std::cin >> num1; std::cout << "\nPlease enter the second number: "; std::cin >> num2; // calculate the quotient of the two numbers here sum = (double)num1 / num2; std::cout << "\nThe quotient of " <<num1<<" and "<<num2<< " is: "<< sum; return 0;}// http://programmingnotes.org/

The above code should give the following output:

`Please enter the first number: 8`

Please enter the second number: 24

The quotient of 8 and 24 is: 0.333333

**==== MODULUS ==== **

If you wanted to capture the remainder of the quotient you calculated from the above code, you would use the modulus operator (%).

From the above code, you would only need to edit line 22, from division, to modulus.

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// ============================================================================// Author: Kenneth Perkins// Date: Jan 4, 2012// Updated: Feb 15, 2021// Taken From: http://programmingnotes.org/// File: modulus.cpp// Description: Demonstrates performing modulus on numbers// ============================================================================#include <iostream>int main(){ int num1 = 0; int num2 = 0; int remainder = 0; std::cout << "Please enter the first number: "; std::cin >> num1; std::cout << "\nPlease enter the second number: "; std::cin >> num2; // find the remainder of the two numbers here remainder = num1 % num2; std::cout << "\nThe remainder of " <<num1<<" and "<<num2<< " is: "<< remainder; return 0;}// http://programmingnotes.org/

The above code should give the following output:

`Please enter the first number: 24`

Please enter the second number: 8

The remainder of 24 and 8 is: 0

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