// 1.7 kiem tra nguyen to

#include<stdio.h>

#include<conio.h>

int (ktra ngto(int a))

main()

{

int i, a;

printf ("

nhap so can kiem tra:");

scanf ("%d",&a);

if (ktra ngto(a))

printf ("

la so nguyen to");

else

printf ("ko la so nguyen to");

getch();

return 0;

}

int ktra ngto(int a)

{

if (a==2)

return 1;

else

{

for (i= 2;i< a; i++)

if (a% i==0)

return 0;

return 1;