C Program to Create Simple Calculator

How to write a C Program to Create Simple Calculator using Switch case, Functions, and Else If Statement.

C Program to Create Simple Calculator Example 1

This calculator program in C helps the user to enter the Operator (+, -, *, or /) and two values. Using those two values and operand, it will perform Arithmetic Operations.

For this C calculator program example, we used the Switch case to check which operand is inserted by the user. Next, based on the Operand result will display.

/* C Program to Create Simple Calculator using Switch Case */
 
#include <stdio.h>
 
int main()
{
	char Operator;
	float num1, num2, result = 0;
	
	printf("\n Please Enter an Operator (+, -, *, /)  :  ");
  	scanf("%c", &Operator);
  	
	printf("\n Please Enter the Values for two Operands: num1 and num2  :  ");
  	scanf("%f%f", &num1, &num2);
  	
  	switch(Operator)
  	{
  		case '+':
  			result = num1 + num2;
  			break;
  		case '-':
  			result = num1 - num2;
  			break;  			
  		case '*':
  			result = num1 * num2;
  			break;
  		case '/':
  			result = num1 / num2;
  			break;
		default:
			printf("\n You have enetered an Invalid Operator ");				    			
	}
  
	printf("\n The result of %.2f %c %.2f  = %.2f", num1, Operator, num2, result);
	
  	return 0;
}

C Program to Create Simple Calculator Example 2

It is the same C program that we used in the first example. But this time, we are performing the arithmetic operation directly inside the Switch case blocks.

#include <stdio.h>
 
int main()
{
	char Operator;
	float num1, num2, result = 0;
	
	printf("\n Please Enter an Operator (+, -, *, /)  :  ");
  	scanf("%c", &Operator);
  	
	printf("\n Please Enter the Values for two Operands: num1 and num2  :  ");
  	scanf("%f%f", &num1, &num2);
  	
  	switch(Operator)
  	{
  		case '+':
  			printf("\n The result of %.2f + %.2f  = %.2f", num1, num2, num1 + num2);
  			break;
  		case '-':
  			printf("\n The result of %.2f - %.2f  = %.2f", num1, num2, num1 - num2);
  			break;  			
  		case '*':
  			printf("\n The result of %.2f * %.2f  = %.2f", num1, num2, num1 * num2);
  			break;
  		case '/':
  			printf("\n The result of %.2f / %.2f  = %.2f", num1, num2, num1 / num2);
  			break;
		default:
			printf("\n You have enetered an Invalid Operator ");				    			
	}
	
  	return 0;
}

 Please Enter an Operator (+, -, *, /)  :  +

 Please Enter the Values for two Operands: num1 and num2  :  125 179

 The result of 125.00 + 179.00  = 304.00P

Program to Create Simple Calculator Example 3

In this example, we are using the Else If Statement to create a simple calculator in c.

#include <stdio.h>
 
int main()
{
	char Operator;
	float num1, num2, result = 0;
	
	printf("\n Please Enter an Operator (+, -, *, /)  :  ");
  	scanf("%c", &Operator);
  	
	printf("\n Please Enter the Values for two Operands: num1 and num2  :  ");
  	scanf("%f%f", &num1, &num2);
  	
  	if(Operator == '+')
  	{
  		printf("\n The result of %.2f + %.2f  = %.2f", num1, num2, num1 + num2);
  	}
  	else if(Operator == '-')
  	{
  		printf("\n The result of %.2f - %.2f  = %.2f", num1, num2, num1 - num2);
  	}
  	else if(Operator == '*')
  	{
  		printf("\n The result of %.2f * %.2f  = %.2f", num1, num2, num1 * num2);
  	}
  	else if(Operator == '/')
  	{
  		printf("\n The result of %.2f / %.2f  = %.2f", num1, num2, num1 / num2);
  	}
  	else
  	{
  		printf("\n You have enetered an Invalid Operator ");
	}
	
  	return 0;
}

 Please Enter an Operator (+, -, *, /)  :  /

 Please Enter the Values for two Operands: num1 and num2  :  1465 32

 The result of 1465.00 / 32.00  = 45.78

Program to Create Simple Calculator Example 4

It is the same calculator program that we used in the first example. However, we separated the C Programming arithmetic operations logic using Functions.

#include <stdio.h>
float add(float a, float b);
float sub(float a, float b);
float multi(float a, float b);
float divi(float a, float b);

int main()
{
	char Operator;
	float num1, num2, result = 0;
	
	printf("\n Please Enter an Operator (+, -, *, /)  :  ");
  	scanf("%c", &Operator);
  	
	printf("\n Please Enter the Values for two Operands: num1 and num2  :  ");
  	scanf("%f%f", &num1, &num2);
  	
  	switch(Operator)
  	{
  		case '+':
  			result = add(num1, num2);
  			break;
  		case '-':
  			result = sub(num1, num2);
  			break;  			
  		case '*':
  			result = multi(num1, num2);
  			break;
  		case '/':
  			result = divi(num1, num2);
  			break;
		default:
			printf("\n You have enetered an Invalid Operator ");				    			
	}
  
	printf("\n The result of %.2f %c %.2f  = %.2f", num1, Operator, num2, result);
	
  	return 0;
}

float add(float a, float b)
{
	return a + b;
}

float sub(float a, float b)
{
	return a - b;
}

float multi(float a, float b)
{
	return a * b;
}

float divi(float a, float b)
{
	return a / b;
}

 Please Enter an Operator (+, -, *, /)  :  -

 Please Enter the Values for two Operands: num1 and num2  :  1462 2932.85

 The result of 1462.00 - 2932.85  = -1470.85