Simple calculator program in C

In this post, you will learn how to write a Simple Calculator program using the C programming language. By using this, you can develop a simple calculator that displays the different arithmetical operations, i.e., addition, subtraction, multiplication, and division.

Algorithm of Simple Calculator

Step 1: Declare local variables
Step 2: Enter any operator at runtime
Step 3: Enter any two integer values at runtime
Step 4: Enter the Choice
Step 5: Apply switch case to select the operator:
           case '+': result = num1 + num2;
               break;
           case '-': result = num1 - num2;
               break;
           case '*': result = num1 * num2;
               break;
           case '/': result = num1 / num2;
               break;
           default: printf("\n Invalid Operator ");
Step 5: Print the result

C program for Simple Calculator

Here is the C program to create a calculator using the switch statement.

#include <stdio.h>
int main(){
   char opt;
   int num1, num2, result = 0;
   printf("\nEnter any one operator( +, -, *, /): ");
   scanf("%c", &opt);
   printf("Enter two numbers : ");
   scanf("%d%d", &num1, &num2);
   switch(opt){
      case '+': 
        printf("%d + %d =\t%d\n",num1,num2,num1+num2);
        break;
      case '-':
        printf("%d - %d =\t%d\n",num1,num2,num1-num2);
        break;
      case '*':
        printf("%d * %d =\t%d\n",num1,num2,num1*num2);
        break;
      case '/': 
        printf("%d / %d =\t%d\n",num1,num2,num1/num2);
        break;
      default: printf("\n Invalid Operator ");
   }
   return 0;
}

Enter any one operator( +, -, *, /): *
Enter two numbers : 79 5
79 * 5 = 395

Enter any one operator( +, -, *, /): +
Enter two numbers : 906 450
906 + 450 = 1356

The * operator entered by the user is stored in opt. And, the two operands, 79 and 5 are stored in first and second respectively.

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