how to read an array of 10 numbers and print the prime numbers?

[greenieM]

this is what i wrote
could someone tell me where is my mistake?
can i use here flag at all?

#include <stdio.h>

void main ()
{
int arr[10], i, j, flag;

for (i=0;i<10;i++)

scanf ("%d", &arr);

for (i=0;i<10;i++)
{
flag=1;


for (j=2;j<=(arr/2); j++)
{
if (arr%j==0)
{
flag=0;
break;

}
}
}

for (i=0;i<10;i++)
{
if (flag=1)

printf ("%d", arr);
}
}

 

[feherke]

Hi

Use equality check instead of setting value :

if (flag=[red]=[/red]1)

Then is a conceptual mistake : you use a single variable to hold the status of all checked numbers. Of course, if the last checked one was prime, will say all were.

Either make the flag an array

#include <stdio.h>

int main ()
{
  int arr[10], i, j, flag[red][10][/red];

  for (i=0;i<10;i++) scanf("%d", &arr[i]);

  for (i=0;i<10;i++) {
    flag[red][i][/red]=1;

    for (j=2;j<=(arr[i]/2); j++) {
      if (arr[i]%j==0) {
        flag[red][i][/red]=0;
        break;
      }
    }
  }

  for (i=0;i<10;i++) {
    if (flag[red][i][/red]) printf("%d", arr[i]);
  }
}

or print the results before ending the second outer loop.

#include <stdio.h>

int main ()
{
  int arr[10], i, j, flag;

  for (i=0;i<10;i++) scanf("%d", &arr[i]);

  for (i=0;i<10;i++) {
    flag=1;

    for (j=2;j<=(arr[i]/2); j++) {
      if (arr[i]%j==0) {
        flag=0;
        break;
      }
    }
    [red]if (flag) printf("%d", arr[i]);[/red]
  }
}

Feherke.

http://rootshell.be/~feherke/