C++ while problem

Question

I have a problem with while loop in c++. I write this code:

#include <iostream.h>
main () {
    int a, av = 0;
    cout << "Enter a number: ";
    cin >> a;

        for (int i = 1; i <= a; i++) {
            while (av == 1) {
                cout << "abc" << a / i;
                if (a % i == 0) {
                    av = 1;
                }
            }
        }
}

This program should print "abc", but it doesn't print any thing. I know the problem is in while section, but how can I fix it? Thanks ..

[The return type of `main()` must be `int`](http://stackoverflow.com/questions/4207134/what-is-the-proper-declaration-of-main/4207223#4207223). The standard library header is named `` (no `.h`). The standard library entities are in the `std` namespace and must be qualified (e.g. `std::cout`, `std::cin`, etc.). — James McNellis, Nov 28 '10 at 17:19

score 3 · Accepted Answer · answered Nov 28 '10 at 17:13

3

It should be while (av == 0) to get in the inner loop.

answered Nov 28 '10 at 17:13

Mariy

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score 3 · Answer 2 · answered Nov 28 '10 at 17:14

3

av is 0 when you get to the while loop so the condition av==1 is always false.

answered Nov 28 '10 at 17:14

WolfgangP

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score 2 · Answer 3 · answered Nov 28 '10 at 17:14

2

At the beginning, av is equal to 0. Its value never gets changed, because the while loop is never entered (since av is NOT equal to 1).

answered Nov 28 '10 at 17:14

Dave McClelland

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score 1 · Answer 4 · answered Nov 28 '10 at 17:14

1

You never initialize av to 1. Try changing your first statement to:

int a, av = 1;

answered Nov 28 '10 at 17:14

johnhforrest

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score 0 · Answer 5 · answered Nov 28 '10 at 17:15

0

Well the while loop will never be entered since av = 0 and the loop predicate is av == 1.

answered Nov 28 '10 at 17:15

ronag

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score 0 · Answer 6 · answered Nov 29 '10 at 11:01

Two cases when abc would not be printed:

1 : The user enters 0 as the input for 'a' - The for loop is exited in the first loop itself as i would never be 0.

2 : initial value of av is 0 and and while (av==1) would never be true irrespective of the number of times the 'for' loop is run

to print abc:

Set av == 1 initially or make sure user enter a number > 0 always

OR

change the code as follows: while (av == 1) { cout << "abc" << a / i; } if (a % i == 0) av = 1;

C++ while problem

6 Answers6