Question

(50 pts) Write a program that asks user an arithmetic operator('+','−','∗' or '/') and two operands and perform the corresponding calculation on the operands. Specific requirements: (1) Your main function accepts inputs and display calculation result.

(2) Write four functions to perform the four calculations. Call these functions in your main function.

(3) Repeatedly asks for inputs, calculate and display result until user input nonnumeric value for operands.

Hint: you can put getchar() right after scanf() to get rid of the newline character that comes though input to scanf(), so it won’t affect the following single character input either by scanf() or getchar().

Answer 1

#include<stdio.h>//header file
//function declaration for calculation
float add(float num1,float num2);
float sub(float num1,float num2);
float mul(float num1,float num2);
float divide(float num1,float num2);
//main function
float main()
{
   char operator;//for opeartor
    float first, second,result;//for operand
    while(1)
    {
    printf("Enter two operands: ");
    /*this condition take input and check whether the data is
    non-numeric or not, scanf always return true or false according to
    input so by using it we check the condition if nonnumeric found
    program will stop*/
    if(scanf(" %f %f", &first, &second) == 0){
    printf("exiting.........\n");
    return 0;
    }
    else
    {  
       printf("Enter an operator (+, -, *,/): ");
        scanf(" %c", &operator);//taking operator from user
       //switch statements for selcting calculation
       switch(operator)
       {
       case '+':
       result = add(first, second);
       break;
       case '-':
       result = sub(first, second);
       break;
       case '*':
       result = mul(first, second);
       break;
      
       case '/':
       result = divide(first, second);
       break;
       }
    printf("%f\n",result);
    }
    }

}
//for addition
float add(float num1,float num2)
{
   float result;
  
   result = num1 + num2;
   return result;
}
//for subtraction
float sub(float num1,float num2)
{
   float result;
  
   result = num1-num2;
   return result;
}
//for multiplication
float mul(float num1,float num2)
{
   float result;  
   result = num1*num2;
   return result;
}
//for divide
float divide(float num1,float num2)
{
   float result;
  
   result = num1/num2;
   return result;
}

Output and code