Prime numbers

[forta2k]

Hello,
I want to make a program which checks how many numbers are 'till it meets number 0.
I've tried this - but it doesn't work.
Can anyone fix it?

  #include <iostream>

using namespace std;

int main()
{
    int n;
    int i;
    int c=0;
    int x;
    cout<<"Enter your number\n";
    cin>>n;
    while(n!=0)
    {
    for (int i=1; i<=n; i++)
    {
    if (n%i==0)
    c++;
    }
    if (c==2)
    {
    x++;
    }
    if (n==0)
        cout<<"The number of prime numbers is:\n";
        cout<<x;
        return 0;
}

[koothkeeper]

This doesn't even compile: Where is the end of your "while" loop?

[forta2k]

It was if(n>0) before I posted. But when I saw it when posting I knew it wasn't right, because it can be negative numbers, I think, but it stops when it meets 0. Can you help me?

[koothkeeper]

Have you tried running it here (click the gear next to your code)?

[forta2k]

No. But if it doesn't even compile, it's not okat anyway.

[koothkeeper]

Add a right curly brace } after line 27.

[ne555]

learn to indent

#include <iostream>

using namespace std;

int main() {
	int n;
	int i;
	int c = 0;
	int x;
	cout << "Enter your number\n";
	cin >> n;
	while(n != 0) {
		for(int i = 1; i <= n; i++) {
			if(n % i == 0)
				c++;
		}
		if(c == 2) {
			x++;
		}
		if(n == 0)
			cout << "The number of prime numbers is:\n";
		cout << x;
		return 0;
	}

there you may notice the missing brace.

> how many numbers are 'till it meets number 0.
I don't understand you, please, rephrase.

> while(n != 0)
you never modify `n', tautology.

	int n;
	int i;
	int c = 0;
	int x;

use meaningful names for your variables, you it's easier to understand what you are doing.

[forta2k]

@ne555:
that's what my friend told me, and I've tried to help him. I didn't really understand either. I think he wants to enter a string of numbers, from x to 0. And the program should display how many prime numbers are in that range.

[bird1234]

1- Brackets are missing
2- While(n!=0)[infinite loop] now what condition is always true you need to use n--; in order to break from loop
3-Always initialize local variable with zero so that the garbage value will not store in the variable
4-i like your problem :)
try this

#include <iostream>

using namespace std;

int main() {
	int n=0;
	int i=0;
	int x= 1;
	cout << "Enter your number\n";
	cin >> n;
	while(n != 0) {
		
		for(int i=2;i<n;i++)
		{
			if(n%i==0)
			break;
			else if(n==i+1)
			x++;
		}
		n--;
	}
	cout<<"The number of prime numbers is:\n";
        cout<<x;
        return 0;
		
}

[ar2007]

change line 8 with:
int x = 1
because i start on loop with i = 2 ; else jump prime number 2

[bird1234]

thnx @ar2007 for identifying my mistake