Question

Question 2:

This program continue asking for a new number until the user enters a 0 to terminate the program

#include <iostream.h>
using namespace std;
int main(void)
{
        int x;
        int count = 0;   // (1) initialize a counter to 0 to count number of values
        int choice = 1; // This is the choice that controls the looping continuation or termination
        double sum = 0; // initialize the sum to 0 to make sure the sum at the beginning is 0
        double average;

        while( choice == 1) // (2) read N grades and compute their sum, count ensures N entries
       {
              // read each number and compute the sum:
             cout << "\n Enter a grade <Enter>: ";
             cin >> x;
             sum = sum + x;
             count++; // (3) update the count
            // prompt the user:
            cout << "Do you wish to enter another grade? (1 for yes and 0 or other key for no): " << endl;
            cin >> choice;
        }

        if(count == 0)
              cout << "You haven't entered any number, no average will be computed, bye \n";
        else{
           average = sum/count; //Notice that we have divided by count this time
            cout << "The average of these " << count << " grades is " << average << endl;
        }

system("pause");

        return 0;
}

In the program,right at the beginning you have initialized the choice to 1. You did that to get the while loop to run at least once. If you use a do ... while instead, you wouldn't need to initialize the choice. Re-write the above program so that is uses do ... while. Do not initialize the choice to 1 this time and compile and run the program. Does the program work the same way?

Thanks so much! If any clarification is needed, just comment.

Answer 1

Modified Program

#include <iostream>

using namespace std;

int main()
{
int x;
int count = 0; // (1) initialize a counter to 0 to count number of values
///********* choice IS NOT INITIALIZED HERE ******************/////
int choice; // This is the choice that controls the looping continuation or termination
double sum = 0; // initialize the sum to 0 to make sure the sum at the beginning is 0
double average;

/***** TO MAKE THE LOOP EXECUTE ATLEAST ONCE WITHOUT CHECKING FOR ANY
* CONDITION, WHILE LOOP IS MODIFIED WITH DO..WHILE LOOP *///
do // (2) read N grades and compute their sum, count ensures N entries
{
// read each number and compute the sum:
cout << "\n Enter a grade <Enter>: ";
cin >> x;
sum = sum + x;
count++; // (3) update the count
// prompt the user:
cout << "Do you wish to enter another grade? (1 for yes and 0 or other key for no): " << endl;
cin >> choice;
}while( choice == 1);

if(count == 0)
cout << "You haven't entered any number, no average will be computed, bye \n";
else{
average = sum/count; //Notice that we have divided by count this time
cout << "The average of these " << count << " grades is " << average << endl;
}

system("pause");

return 0;
}

===============================================================================

#include <iostream> using namespace std; int main() { int x; **///// int count = 0; // (1) initialize a counter to o to count number of values ///********* choice IS NOT INITIALIZED HERE ***** int choice; // This is the choice that controls the looping continuation or termination double sum 0; // initialize the sum to o to make sure the sum at the beginning is double average; /***** TO MAKE THE LOOP EXECUTE ATLEAST ONCE WITHOUT CHECKING FOR ANY CONDITION, WHILE LOOP IS MODIFIED WITH DO..WHILE LOOP */// do // (2) read N grades and compute their sum, count ensures N entries نفسه // read each number and compute the sum: cout << "\n Enter a grade <Enter>: "; cin >> X; sum = sum + x; count++; // (3) update the count // prompt the user: cout << "Do you wish to enter another grade? (1 for yes and or other key for no): cin >> choice; }while( choice 11 << endl; 1);

if(count 0) cout << "You haven't entered any number, no average will be computed, bye \n"; else{ average = sum/count; //Notice that we have divided by count this time cout << "The average of these " << count << "grades is " « average << endl; بہ system("pause"); return 0; }

Enter a grade <Enter>: 60 Do you wish to enter another grade? (1 for yes and 0 or other key for no): 1 Enter a grade <Enter>: 89 Do you wish to enter another grade? (1 for yes and 0 or other key for no): 1 Enter a grade <Enter>: 56 Do you wish to enter another grade? (1 for yes and 0 or other key for no): 1 Enter a grade <Enter>: 98 Do you wish to enter another grade? (1 for yes and 0 or other key for no): 0 The average of these 4 grades is 75.75