# C Program for Addition Subtraction Multiplication Division using Function

Here we will write a C program for addition subtraction multiplication and division using the function. First, we will create a simple program to solve the program, then we will write the same program where input is taken and the result is displayed using functions. At last, we will develop a menu-driven program, where the user has a choice, which operation he/she wants to perform addition or subtraction or multiplication or division. Previously we had already developed a program for addition, subtraction, multiplication, and division operation but without using the function.

## C Program for Addition Subtraction Multiplication and Division using the Function

Program description:- C program for addition subtraction multiplication and division using the function.

``````#include<stdio.h>

// functions declaration
int subtract(int n1, int n2);
int multiply(int n1, int n2);
int divide(int n1, int n2);

// main function
int main()
{
int num1, num2;

printf("Enter two numbers: ");
scanf("%d %d", &num1, &num2);

printf("%d + %d = %d\n", num1, num2, add(num1, num2));
printf("%d - %d = %d\n", num1, num2, subtract(num1, num2));
printf("%d * %d = %d\n", num1, num2, multiply(num1, num2));
printf("%d / %d = %d\n", num1, num2, divide(num1, num2));

return 0;
}

// function to add two integer numbers
{
int result;
result = n1 + n2;
return result;
}

// function to subtract two integer numbers
int subtract(int n1, int n2)
{
int result;
result = n1 - n2;
return result;
}

// function to multiply two integer numbers
int multiply(int n1, int n2)
{
int result;
result = n1 * n2;
return result;
}

// function to divide two integer numbers
int divide(int n1, int n2)
{
int result;
result = n1 / n2;
return result;
}``````

Output for the different test-cases:-

Enter two numbers: 20 5
20 + 5 = 25
20 – 5 = 15
20 * 5 = 100
20 / 5 = 4

In this program we have taken two integer numbers, you can also take floating-point numbers in your own program. But in that case inside every function replace the int keyword with a float or double.

## Program2

Program:- Write a C program for addition subtraction multiplication and division. Perform every operation through function. Take input inside a user-defined function, and also display the result from another user-defined function.

``````#include<stdio.h>

// function declarations
int input();
void display(int n1, int n2, char ch, int result);
void subtract(int n1, int n2);
void multiply(int n1, int n2);
void divide(int n1, int n2);

// main function
int main()
{
int n1, n2;
n1 = input();
n2 = input();

subtract(n1, n2);
multiply(n1, n2);
divide(n1, n2);
return 0;
}

// function for taking input from user
int input()
{
int n;
printf("Enter number: ");
scanf("%d",&n);
return n;
}

// function for displaying the result.
void display(int n1, int n2, char ch, int result)
{
printf("%d %c %d = %d\n", n1, ch, n2, result);
}

// function for addition of two numbers
{
int result;
result = n1 + n2;
display(n1, n2, '+', result);
}

// function for subtraction of two numbers
void subtract(int n1, int n2)
{
int result;
result = n1 - n2;
display(n1, n2, '-', result);
}

// function for multiplication of two numbers
void multiply(int n1, int n2)
{
int result;
result = n1 * n2;
display(n1, n2, '*', result);
}

// function for division of two numbers
void divide(int n1, int n2)
{
int result;
result = n1 / n2;
display(n1, n2, '/', result);
}``````

Output:-

Enter number: 19
Enter number: 9
19 + 9 = 28
19 – 9 = 10
19 * 9 = 171
19 / 9 = 2

Program description:- Write a menu-driven program to find addition, subtraction, multiplication, and division of two numbers using the user defined functions and the program should accept choice from the user repeatedly.

``````#include<stdio.h>

// function for taking input from user
float input()
{
float n;
scanf("%f",&n);
return n;
}

// function for displaying the result
void display(float n1, float n2, char ch, float result)
{
printf("%.2f %c %.2f = %.2f\n", n1, ch, n2, result);
}

// function for addition of two numbers
{
float result;
result = n1 + n2;
display(n1, n2, '+', result);
}

// function for subtraction of two numbers
void subtract(float n1, float n2)
{
float result;
result = n1 - n2;
display(n1, n2, '-', result);
}

// function for multiplication of two numbers
void multiply(float n1, float n2)
{
float result;
result = n1 * n2;
display(n1, n2, '*', result);
}

// function for division of two numbers
void divide(float n1, float n2)
{
float result;
result = n1 / n2;
display(n1, n2, '/', result);
}

// main function
int main()
{
char ch;
int choice;
float n1, n2;

// do-while loop
do
{
printf("Enter first number: ");
n1 = input();
printf("Enter second number: ");
n2 = input();

printf("\nWhich operation you want to perform,\n");
printf("2.Subtraction\n");
printf("3.Multiplication\n");
printf("4.Division\n");
scanf("%d", &choice);

switch (choice) {
case 1:
break;
case 2:
subtract(n1, n2);
break;
case 3:
multiply(n1, n2);
break;
case 4:
divide(n1, n2);
break;
default:
printf("Invalid choice");
}

printf("\nDo you want to continue (y/n): ");
scanf("%c",&ch);
scanf("%c",&ch);
printf("***************************************\n");

} while(ch=='y');

printf("\nThank You.");
return 0;
}``````

Output Samples:-

Enter first number: 10
Enter second number: 5

Which operation you want to perform,
2.Subtraction
3.Multiplication
4.Division
10.00 + 5.00 = 15.00

Do you want to continue (y/n): y
***************************************
Enter first number: 15
Enter second number: 10

Which operation you want to perform,
2.Subtraction
3.Multiplication
4.Division
15.00 – 10.00 = 5.00

Do you want to continue (y/n): y
***************************************
Enter first number: 5
Enter second number: 2

Which operation you want to perform,
2.Subtraction
3.Multiplication
4.Division
5.00 * 2.00 = 10.00

Do you want to continue (y/n): y
***************************************
Enter first number: 40
Enter second number: 8

Which operation you want to perform,
2.Subtraction
3.Multiplication
4.Division
40.00 / 8.00 = 5.00

Do you want to continue (y/n): n
***************************************

Thank You.

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