Calculator Program in C

In this topic, we will discuss how we write a calculator program in the C programming language. A Calculator is a small electronic device used to perform various arithmetic operations like addition, subtraction, multiplication, division, percentage, etc. It makes our calculations easier and faster. It is a portable device that can use anywhere to perform simple mathematical operations. We use a scientific or sophisticated calculator in some situations, where we need to solve complex calculations like trigonometry functions, exponential operators, degrees, radians, log functions, hyperbolic functions etc. Let's discuss the various ways to create a calculator program in the C language.

Algorithm of Calculator Program

Step 1: Declare local variables n1, n2, res, opt. For example, where n1 and n2 take two numeric values, res will store results and opt variable define the operator symbols.

Step 2: Print the Choice (Addition, Subtraction, multiplication, division, etc.

Step 3: Enter the Choice

Step 4: Takes two numbers, n1 and n2

Step 5: Switch case jump to an operator selected by the user

Step 6: Store result into res variable.

Step 7: Display the operation result

Step 8: Exit from the program.

Different ways to create a Calculator Program in C

Following are the different ways to write a Calculator Program in the C language.

Calculator Program in C using the switch statement
Calculator Program in C using if else if statement
Calculator Program in C using do-while loop and switch statement
Calculator Program in C using function and switch statement

Example 1: Calculator Program in C using the switch statement

Let's write a program to create a Calculator program using switch statement

program.c

#include <stdio.h>
int main()
{
	// declare local variables
	char opt;
	int n1, n2; 
	float res;
	printf (" Choose an operator(+, -, *, /) to perform the operation in C Calculator \n ");
	scanf ("%c", &opt); // take an operator
	if (opt == '/' )
	{
		printf (" You have selected: Division");
	}
	else if (opt == '*')
	{
		printf (" You have selected: Multiplication");
	 }
	 
	else if (opt == '-')
	{
		printf (" You have selected: Subtraction");
	 }
	 	else if (opt == '+')
	{
		printf (" You have selected: Addition");
	 }   
	printf (" \n Enter the first number: ");
	scanf(" %d", &n1); // take fist number
	printf (" Enter the second number: ");
	scanf (" %d", &n2); // take second number
	
	switch(opt)
	{
		case '+':
			res = n1 + n2; // add two numbers
			printf (" Addition of %d and %d is: %.2f", n1, n2, res);
			break;
		
		case '-':
			res = n1 - n2; // subtract two numbers
			printf (" Subtraction of %d and %d is: %.2f", n1, n2, res);
			break;
			
		case '*':
			res = n1 * n2; // multiply two numbers
			printf (" Multiplication of %d and %d is: %.2f", n1, n2, res);
			break;			
		
		case '/':
			if (n2 == 0)   // if n2 == 0, take another number
			{
				printf (" \n Divisor cannot be zero. Please enter another value ");
				scanf ("%d", &n2);		
				}
			res = n1 / n2; // divide two numbers
			printf (" Division of %d and %d is: %.2f", n1, n2, res);
			break;
		default:  /* use default to print default message if any condition is not satisfied */
			printf (" Something is wrong!! Please check the options ");				
	}
	return 0;
}

Output:

Example 2: Calculator Program in C using if else if statement

Let's consider an example to write a simple Calculator program in C using if else if statement.

program2.c

#include <stdio.h>
int main()
{
	// declare local variables
	char opt;
	int n1, n2; 
	float res;
	printf (" Select an operator (+, -, *, /) to perform an operation in C calculator \n ");
	scanf ("%c", &opt); // take an operator
	printf (" Enter the first number: ");
	scanf(" %d", &n1); // take fist number
	printf (" Enter the second number: ");
	scanf (" %d", &n2); // take second number
	
	if (opt == '+')
	{
		res = n1 + n2; // add two numbers
		printf (" Addition of %d and %d is: %f", n1, n2, res);
	}
	
	else if (opt == '-')
	{
		res = n1 - n2; // subtract two numbers
		printf (" Subtraction of %d and %d is: %f", n1, n2, res);
	}
	
	else if (opt == '*')
	{
		res = n1 * n2; // multiply two numbers
		printf (" Multiplication of %d and %d is: %f", n1, n2, res);
	}
	
	else if (opt == '/')
	{
		if (n2 == 0)   // if n2 == 0, take another number
		{
			printf (" \n Divisor cannot be zero. Please enter another value ");
			scanf ("%d", &n2);		
		}
		res = n1 / n2; // divide two numbers
		printf (" Division of %d and %d is: %.2f", n1, n2, res);
	}
	else
	{
		printf(" \n You have entered wrong inputs ");
	}
	return 0;
}

Output:

Example 3: Calculator Program in C using do while loop and switch statement

Let's create a Calculator program using do while loop and switch case statement in C

program3.c

#include <stdio.h>
#include <math.h>
#include <stdlib.h>

int main()
{
	// declaration of local variable op;
	int op, n1, n2;
	float res;
	char ch;
	do
	{
		// displays the multiple operations of the C Calculator
		printf (" Select an operation to perform the calculation in C Calculator: ");
		printf (" \n 1 Addition  \t \t 2 Subtraction \n 3 Multiplication \t 4 Division \n 5 Square \t \t 6 Square Root \n 7 Exit \n \n Please, Make a choice ");	
		
		scanf ("%d", &op); // accepts a numeric input to choose the operation
	
	
	// use switch statement to call an operation
	switch (op)
	{
		case 1:
			// Add two numbers
			printf (" You chose: Addition");
			printf ("\n Enter First Number: ");
			scanf (" %d", &n1);
			printf (" Enter Second Number: ");
			scanf (" %d", &n2);
			res = n1 + n2; // Add two numbers
			printf (" Addition of two numbers is: %.2f", res);
			break; // break the function
			
		case 2:
			// Subtract two numbers
			printf (" You chose: Subtraction");
			printf ("\n Enter First Number: ");
			scanf (" %d", &n1);
			printf (" Enter Second Number: ");
			scanf (" %d", &n2);
			res = n1 - n2; // subtract two numbers
			printf (" Subtraction of two numbers is: %.2f", res);
			break; // break the function
			
		case 3:
			// Multiplication of the numbers
			printf (" You chose: Multiplication");
			printf ("\n Enter First Number: ");
			scanf (" %d", &n1);
			printf (" Enter Second Number: ");
			scanf (" %d", &n2);
			res = n1 * n2; // multiply two numbers
			printf (" Multiplication of two numbers is: %.2f", res);
			break; // break the function
			
		case 4:
			// Division of the numbers
			printf (" You chose: Division");
			printf ("\n Enter First Number: ");
			scanf (" %d", &n1);
			printf (" Enter Second Number: ");
			scanf (" %d", &n2);
			if (n2 == 0)
				{
					printf (" \n Divisor cannot be zero. Please enter another value ");
					scanf ("%d", &n2);		
				}
			res = n1 / n2; // divide two numbers
			printf (" Division of two numbers is: %.2f", res);
			break; // break the function
			
		case 5:
			// getting square of a number
			printf (" You chose: Square");
			printf ("\n Enter First Number: ");
			scanf (" %d", &n1);

			res = n1 * n1; // get square of a number
			printf (" Square of %d number is: %.2f", n1, res);
			break; // break the function
			
		case 6:
			// getting the square root of the number
			printf (" You chose: Square Root");
			printf ("\n Enter First Number: ");
			scanf (" %d", &n1);
			
			res = sqrt(n1); // use sqrt() function to find the Square Root 
			printf (" Square Root of %d numbers is: %.2f", n1, res);
			break; // break the function
			
		case 7:
			printf (" You chose: Exit");
			exit(0); 
			break; // break the function
			
		default:
			printf(" Something is wrong!! ");
			break; 						
	}
	printf (" \n \n ********************************************** \n ");
	} while (op != 7);

	return 0;      
}

Output:

Example 4: Calculator Program in C using function and switch statement

Let's create a Calculator program using function and switch case statement in C

program4.c

#include <stdio.h>
#include <conio.h>
#include <math.h>
#include <stdlib.h>
	
// function declarations 
int addition();
int subtract();
int multiply();
int divide();
int sq();
int sqrt1();
void exit();

int main()
{
	// declaration a local variable op;
	int op;
	do
	{
		// displays the multiple operations of the C Calculator
		printf (" Select an operation to perform the calculation in C Calculator: ");
		printf (" \n 1 Addition  \t \t 2 Subtraction \n 3 Multiplication \t 4 Division \n 5 Square \t \t 6 Square Root \n 7 Exit \n \n Please, Make a choice ");	
		
		scanf ("%d", &op); // accepts a numeric input to choose the operation
	
	
	// use switch statement to call an operation
	switch (op)
	{
		case 1:
			addition(); /* It call the addition() function  to add the given numbers */
			break; // break the function
			
		case 2:
			subtract(); /* It call the subtract() function  to subtract the given numbers */
			break; // break the function
			
		case 3:
			multiply(); /* It call the multiply() function  to multiply the given numbers */
			break; // break the function
			
		case 4:
			divide(); // It call the divide() function  to divide the given numbers
			break; // break the function
			
		case 5:
			sq(); // It call the sq() function  to get the square of given numbers
			break; // break the function
			
		case 6:
			sqrt1(); /* It call the sqrt1() function  to get the square root of given numbers */
			break; // break the function
			
		case 7:
			exit(0); // It call the exit() function  to exit from the program
			break; // break the function
			
		default:
			printf(" Something is wrong!! ");
			break; 						
	}
	printf (" \n \n ********************************************** \n ");
	} while (op != 7);
	

	return 0;      
}



// function definition
int addition()
{
	int i, sum = 0, num, f_num; // declare a local variable	
	printf (" How many numbers you want to add: ");
	scanf ("%d", &num);
	printf (" Enter the numbers: \n ");
	for (i = 1; i <= num; i++)
	{
		scanf(" %d", &f_num);
		sum = sum + f_num;
	}
	printf (" Total Sum of the numbers = %d", sum);
	return 0;
}

// use subtract() function to subtract two numbers
int subtract()
{
	int n1, n2, res;
	printf (" The first number is: ");
	scanf ("  %d", &n1);
	printf (" The second number is: ");
	scanf ("  %d", &n2);
	res = n1 - n2;	
	printf (" The subtraction of %d - %d is: %d", n1, n2, res);
}

// use multiply() function to multiply two numbers
int multiply()
{
	int n1, n2, res;
	printf (" The first number is: ");
	scanf ("  %d", &n1);
	printf (" The second number is: ");
	scanf ("  %d", &n2);
	res = n1 * n2;	
	printf (" The multiply of %d * %d is: %d", n1, n2, res);
}

// use divide() function to divide two numbers
int divide()
{
	int n1, n2, res;
	printf (" The first number is: ");
	scanf ("  %d", &n1);
	printf (" The second number is: ");
	scanf ("  %d", &n2);
	
	if (n2 == 0)
	{
		printf (" \n Divisor cannot be zero. Please enter another value ");
		scanf ("%d", &n2);		
	}
	res = n1 / n2;	
	printf (" \n The division of %d / %d is: %d", n1, n2, res);
}

// use sq() function to get the square of the given number
int sq()
{
	int n1, res;
	printf (" Enter a number to get the Square: ");
	scanf ("  %d", &n1);
	
	res = n1 * n1;	
	printf (" \n The Square of %d is: %d", n1, res);
}

// use sqrt1() function to get the square root of the given number 
int sqrt1()
{
	float res;
	int n1;
	printf (" Enter a number to get the Square Root: ");
	scanf ("  %d", &n1);

	res = sqrt(n1);	
	printf (" \n The Square Root of %d is: %f", n1, res);
}

Output:

Next TopicCalloc in C

← prev next →

For Videos Join Our Youtube Channel: Join Now

Feedback

Send your Feedback to [email protected]

Help Others, Please Share

Learn Latest Tutorials

Splunk

SPSS

Swagger

Transact-SQL

Tumblr

ReactJS

Regex

Reinforcement Learning

R Programming

RxJS

React Native

Python Design Patterns

Python Pillow

Python Turtle

Keras

Preparation

Aptitude

Reasoning

Verbal Ability

Interview Questions

Company Questions

Trending Technologies

Artificial Intelligence

AWS

Selenium

Cloud Computing

Hadoop

ReactJS

Data Science

Angular 7

Blockchain

Git

Machine Learning

DevOps

B.Tech / MCA

DBMS

Data Structures

DAA

Operating System

Computer Network

Compiler Design

Computer Organization

Discrete Mathematics

Ethical Hacking

Computer Graphics

Software Engineering

Web Technology

Cyber Security

Automata

C Programming

C++

Java

.Net

Python

Programs

Control System

Data Mining

Data Warehouse

Javatpoint Services

JavaTpoint offers too many high quality services. Mail us on h[email protected], to get more information about given services.

Website Designing
Website Development
Java Development
PHP Development
WordPress
Graphic Designing
Logo
Digital Marketing
On Page and Off Page SEO
PPC
Content Development
Corporate Training
Classroom and Online Training
Data Entry

Training For College Campus

JavaTpoint offers college campus training on Core Java, Advance Java, .Net, Android, Hadoop, PHP, Web Technology and Python. Please mail your requirement at [email protected].
Duration: 1 week to 2 week

^{Like/Subscribe us for latest updates or newsletter}

C Tutorial

C Control Statements

C Functions

C Array

C Pointers

C Dynamic Memory

C Strings

C Math

C Structure Union

C File Handling

C Preprocessor

C Command Line

C Misc

C Programming Test

C Programs

MCQ

Math

C Interview

Calculator Program in C

Algorithm of Calculator Program

Different ways to create a Calculator Program in C

Example 1: Calculator Program in C using the switch statement

Example 2: Calculator Program in C using if else if statement

Example 3: Calculator Program in C using do while loop and switch statement

Example 4: Calculator Program in C using function and switch statement

Feedback

Help Others, Please Share

Learn Latest Tutorials

Preparation

Trending Technologies

B.Tech / MCA

Javatpoint Services

Training For College Campus