Question

C Programming

QUESTION 9

1. Write a program that prompts for and reads four integer input values, then a single character command. Submit your program as a .c file named midterm_prog2.c. Note that, similarly to your programming assignments, some percentage of your grade will depend on proper programming style.

   Your program will calculate and print a new value based on the command that's entered, as follows:

   • 'A' or 'a': Calculate the average of the four input values
   • 'S' or 's': Calculate the standard deviation of the four input values
     • Your program must include the math library and use the sqrt() function, which returns the square root of its input argument, to calculate standard deviation
   • 'M' or 'm': Calculate the maximum value among the four input values

   If the user enters any other command, your program should print an error message that contains the invalid character. This program does not need to test for any other errors.

   If you don't know how to calculate any of those statistics, a quick web search should help you find the answers.

   Your output should match the format of the test cases shown below exactly. In each test case, the sample input values are underlined.

   TEST CASE 1:

   Enter input vals: 6 16 20 19
   Enter command: A
   Average: 15.250

   TEST CASE 2:
   
   Enter input vals: 5 -5 10 -2
   Enter command: s
   Standard deviation: 5.874
   
   
   TEST CASE 3:
   
   Enter input vals: 9 12 -1 3
   Enter command: M
   Maximum value: 12
   
   
   TEST CASE 4
   
   Enter input vals: 15 9 27 3
   Enter command: T
   Invalid command T

Answer 1

The below is the c code for the given requirement.

#include <stdio.h>
int main()

{

   int a,b,c,d,sum,max;
   int avg,i;
   int i1,b1,c1,d1;
   int count,mean,sod,variance,standev;
   char val;   

   printf("Enter input vals:");
   scanf("%d%d%d%d",&a,&b,&c,&d);
   i=a;
   printf("Enter command:");
   scanf("%s",&val);
  
   switch (val)
   {
      
       case 'A':   sum=(i+b+c+d);
           avg=(sum/4);
               printf("Average:%d\n",avg);
               break;

       case 'S':  
              
               count=4;
               sum=(i+b+c+d);
               mean=sum/4;

               i=i-mean;
               b=b-mean;
               c=c-mean;
               d=d-mean;

               i1=i*i;
               b1=b*b;
               c1=c*c;
               d1=d*d;

               sod=i1+b1+c1+d1;
               variance=sod/4;
               standev=sqrt(variance);

               printf("Standard deviation:%d\n",standev);
               break;

       case 'M':  
               max=((i>b? i:b) > (c>d? c:d) ? (i>b? i:b) : (c>d? c:d));
               printf("Maximum value:%d\n",max);
               break;
      
       default:  
               printf("Invalid command\n");
               break;
   }

}