Question

Write a program named problem.c to generate addition and subtraction math problems for a 4th grader.

1. Your program will first ask user how many problems they want to do.

2. Repeat the following until you give user the number of problems that the user asks for.

  a. Display the question number

b. Generate a addition or subtraction problem using two random generated two digits (0-99).

- The odd number of problems (1,3,5,…) will be addition problems.

- The even number of problems (2,4,6,…) will be subtraction problems. For subtraction problem, swap two numbers if the first number is smaller than the second number.

c. Display the problem, then ask user to answer. If the user answers correctly the first time, the user gets 10 points for the problem. If the user does not answer correctly, you print the problem again, and ask the user to try again. If the user answers correctly second time, the user gets 5 points for this problem. You then display the total points that user gets.

4. Calculate and display the percentage. a. If the percentage is above or equal 93%, display “Excellent”. b. If the percentage is above or equal 87%, display “Very good”. c. Otherwise, print “Keep working hard.”

Output shown look like:

How many problems would you like to do today?4

Ok! You will be given 4 math problems.

Good luck with them! Press enter to start.

Question 1

92 + 11 = 103

Correct! 10 points. Total points: 10

Question 2

95 - 10 = 85

Correct! 10 points. Total points: 20

Question 3

31 + 56 = 87

Correct! 10 points. Total points: 30

Question 4

32 - 29 = 2

Wrong. Please try again.

32 - 29 = 3

Correct. 5 points. Total points: 35

You got 87.50%! Very Good!

Thank you for using my math problem generator!

Answer 1

#include<stdio.h>
#include<stdlib.h>
int main()
{
    //variable declaration
    int a,b,n,ans,point=0,count=0,i;
    double percentage;
    //ask for number of problems
    printf("\n How many problems would you like to do today?");
    scanf("%d",&n);
    //loop will continue from 1 to n
    for(count=1;count<=n;count++)
    {
       a=rand()%100; //generate first random number between 0 to 99 inclusive
       b=rand()%100; //generate second random number between 0 to 99 inclusive
       if(count%2==0) //check for even number
       { i=1; //set the counter for number of attempts
          printf("\n Question %d",count); //display the question number
          if(a<b) //swap if a<b
          {
             a=a+b;
             b=a-b;
             a=a-b;
           }
          while(i<3) //loop will continue 2 times at most
          {
               printf("\n %d - %d = ",a,b); //display the question
               fflush(stdin);
               scanf("%d",&ans);//read answer
             if(ans==(a-b) && i==1) //check the validity of answer in first attempt
               {
                   point = point+10; //update the point
                   printf("\n Correct! 10 points, Total points %d",point);
                   break;//terminate loop
                   }
                   else  
                   if(ans==(a-b) && i==2)//check the validity of answer in second attempt
               {
                   point = point+5;//update the point
                   printf("\n Correct! 5 points, Total points %d",point);
                   break;//terminate loop
                   }
                   else //display message for wrong answer
                   printf("\n Wrong. Please Try again");
                   i++; //increment the counter for while loop
               }            
               }
   else
   {
       i=1;
          printf("\n Question %d",count);  
          while(i<3)//loop will continue 2 times at most
          {
               printf("\n %d + %d = ",a,b);//display the question
               fflush(stdin);
               scanf("%d",&ans);//read answer
             if(ans==(a+b) && i==1) //check the validity of answer in first attempt
               {
                   point = point+10;//update the point
                   printf("\n Correct! 10 points, Total points %d",point);
                   break;//terminate loop
                   }
                   else
                   if(ans==(a+b) && i==2)//check the validity of answer in second attempt
               {
                   point = point+5;//update the point
                   printf("\n Correct! 5 points, Total points %d",point);
                   break;//terminate loop
                   }
                   else//display message for wrong answer
                   printf("\n Wrong. Please Try again");
                   i++;//increment the counter for while loop
               }            
               }
   }
   //display the final point
   printf("\n Total Points : %d",point);
   //computing the percentage
   percentage = (double)(point)/(n*10);
   percentage = percentage * 100;
   //block for percentage above or equal to 93
   if(percentage>=93)
   printf("\n You got %5.2lf! Excellent!",percentage);
   else
   if(percentage>=87) //block for percentage above or equal to 87
   printf("\n You got %5.2lf! Very Good!",percentage);
   else
   printf("\n You got %5.2lf! Keep working very hard",percentage);
   //display the thank you message
   printf("\n Thank you for using my math problem generator!");
}

OUTPUT