I am trying to make a program that indicates prime numbers and this is what i have so far but i am not quite sure what the problem is. This is what the instructor has told me to make

"
For this project, you will read in values from the user until he enters the letter ‘q’. Each parameter should be a positive integer, but if the user enters a value that is not a positive integer, you should tell him that your program only accepts positive integers, then prompt him to enter a number. (See example below)

If the user enters a positive integer, you will determine whether or not the number is prime or composite. A number is defined to be prime if the only divisors of that number are 1 and itself. If a number is not prime, then it is composite. In other words:

Assuming n,d ÎZ
Prime(n) = false Û n/d ÎZ where d Ï {1, n}
Prime(n) = true otherwise

Your program should test the primality of each number on the command line. The output should be the number followed by the word “PRIME” or “COMPOSITE” depending on whether the number is prime or composite. Also, if the number happens to be composite, your program should also print out the largest integer, other than 1 or n, that divides the number evenly.

In addition, you need to use at least 3 functions in your program. You can make the functions do whatever you would like, but you must have at least 3.

Here is a possible execution of your program. The user input is bolded.

Please enter a positive integer: 10
10 COMPOSITE 5

Please enter a positive integer: 7
7 PRIME

Please enter a positive integer: a
‘a’ is not a positive integer.

Please enter a positive integer: 93
93 COMPOSITE 31

Please enter a positive integer: 101
101 PRIME

Please enter a positive integer: q
Thank you for using my program."


AND THIS IS THE PROGRAM I HAVE WRITTEN SO FAR.

#include <stdio.h>
#include <math.h>
#include <string.h>
int prime(n);
void main () {
int n;
int d;
int z;
int i=1;
char ch;
printf ("Enter a positive integer:");
scanf ("%d", &n);

for (d = 1; d <= i; d++) {
z=0;
printf ("%d Prime",n);
}
while (i <= n){
}

if (i%d==0) {

}
if(z==2){
printf("%d",i);
i++;
}
else {
printf ("%d composite\n", n, n+1);
}
printf ("\nPress 'q' to exit\n");
printf ("\nThank you for using my program");
scanf("%c", &ch);
while (ch != 'q') {
scanf("%c", &ch);
}
}

__________________

---

That code is not Visual basic, its C++ isnt it?, please confirm what it really is and i can move to the correct area.

__________________

---

Out of curiosity, why do you use for ... loops?
I think for this one, it's better if you use do .. while...

do something, while the user does not input -1 for example, or in your case 'q'

I think it's C. wrong section eh?

__________________

---

yeah this is for Microsoft visual C. I wasnt to sure what to use so I just started off my program with for

__________________

---

Should have posted here:
http://www.programmerstalk.net/forum2.html

Many C/C++ experts there, even I'm learning C++ too now
But I hope I can catch it a little faster so that I can continue again with my lovely ASP.NET

__________________

---

Yup, wrong section - admin, move it to the C++ forum and we'll answer it there

__________________
Day Cares | Golf Courses | Disc Golf Courses | Campgrounds | Ice Rinks | Paintball Fields | Dentists | Plastic Surgeons | Aging Jokes
Catholic Churches | Lutheran Churches | Methodist Churches | Episcopal Churches | Clean Jokes

---

Can you explain the problem a bit more? I understand that you don't know what the problem with the code is, but what does it do that is wrong? For example, what output do you get that you shouldn't be getting? Give some sample output, like the example that you included from your instructions.

__________________
"C makes it easy to shoot yourself in the foot; C++ makes it harder, but when you do it blows your whole leg off."
-- Bjarne Stroustrup, creator of what is now known as C++
For more quotes by Bjarne Stroustrup, check out http://www.research.att.com/~bs/bs_faq.html#really-say-that.

---

when i type in the code everything is prime. My logic to the program is incorrect i believe because any number i type in it ends up to be prime. Also if the number is not prime it should have "#inputted composite (biggest divisible number)"

__________________

---

Any suggestions on what i should do?

__________________

---

Sorry, what does this line do?



I personally never tried C programming out lol... It's kind of similar with C++ though (which is something that I'm doing right now lol...)

I'm just wondering how to get the logic to figure out whether it's a composite, composite means that it has at least one factor right?

__________________

---