In this example, you will learn to create a  
 c program To make a simple calculator.






  • To Understand The program you need the basic Knowledge of

      1)  C switch statement
     2)  Break and continue


Switch case Syntax


switch (expression)
​{
    case constant1:
      // statements
      break;

    case constant2:
      // statements
      break;
    .
    .
    .
    default:
      // default statements
}

  • This program takes an arithmetic operator from the user Like this (+,-,*,/) .And two operands from the user (or you can say that two numbers input from the user).

  • Then it performs the calculation on the two operands according to the operator that user entered. 




  • Here, we will create a simple calculator program in C which will perform basic arithmetic operations like addition, subtraction, multiplication, division, and remainder depending on the input from the user.

  • Users will have the choice to choose the operation. If the user chooses the wrong operation then he/she will get an error message.


Simple Calculator Using Switch statement


#include <stdio.h>
 int main()

{
 char op;
 double first, second;
 printf("Enter an operator (+, -, *, /): ");
 scanf("%c", &op);
 printf("Enter two operands: ");
 scanf("%lf %lf", &first, &second); switch (op) {
 case '+':
 printf("%.1lf + %.1lf = %.1lf", first, second, first + second);
 break;
 case '-':
 printf("%.1lf - %.1lf = %.1lf", first, second, first - second);
 break;
 case '*':
 printf("%.1lf * %.1lf = %.1lf", first, second, first * second);
 break;
 case '/':
 printf("%.1lf / %.1lf = %.1lf", first, second, first / second);
 break;
 // operator doesn't match any case constant
 default:
 printf("Error! operator is not correct");
 } return 0;
}



Output

Enter an operator (+, -, *,): *
Enter two operands: 1.5
4.5
1.5 * 4.5 = 6.8




Explanation 


  • The * operator entered by the user is stored in op. And, the two operands, 1.5 and 4.5 are stored in first and second respectively.

  • Since the operator * matches case '*':, the control of the program jumps to

printf("%.1lf * %.1lf = %.1lf", first, second, first * second);

  • This statement calculates the product and displays it on the screen.
  • To make our output look cleaner, we have simply limited the output to one decimal place using the code %.1lf.
  • Finally, the break; statement ends the switch statement.

  •  If the entered operator is not matched with the case labels then the default statement will be executed and it will display the message
  •  "Error! operator is not correct"


Enter an operator (+, -, *,): %
Enter two operands: 1.5
4.5
 "Error! operator is not correct"


EXAMPLE-2  (Using else -if statement)

In The previous example we use the switch case to perform a c program to make a simple calculator.

And in this example we make a c program to make a simple calculator using simple if else-if statement.


  • To Understand The program you need the basic Knowledge of

      1)  C else if _ if else
      2)  c operator


/* C Program to Create Simple Calculator using Else If */

 

#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;

}


Output

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

Please Enter the Values for two Operands: num1 and num2  :  14 2

The result of 14 + 2  = 16


Explanation

  • The (+) operator entered by the user is stored in (operator). And, the two operands, 14  and 2 are stored in first and second respectively.

  • Then it check all The else-if condition Since the operator  (+) matches  
  •  the control of the program jumps to. This




if(Operator == '+')
    {
        printf("\n The result of %.2f + %.2f  = %.2f", num1, num2, num1 + num2);
    }


Also check Out





  Q-2)  pointers in c




  

   Q-3) Vector Sort


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