Program
code
#include
<stdio.h>
#include
<conio.h>
void
main()
{
int
question=0, i=2;
clrscr();
printf(“Please
input a positive integer to find out whether it is a prime number or composite
number.\n”);
scanf(“%d”,&question);
if
(question==1)
{
printf(“%d
is neither prime nor composite.\n”, question);
goto
stop;
}
if
(question==2)
{
printf(“%d
is a prime number.\n%d is the only even prime number.\n”,question,question);
goto
stop;
}
do
{
if
(question%i==0)
{
printf(“%d
is a composite number.\n”,question);
goto
stop;
}
i++;
}
while(i<question);
printf(“%d
is a prime number.\n”,question);
stop:
getch();
}
Example
of output
Please
input a positive integer to find out whether it is a prime number or composite
number.
3
3
is a prime number.
