#include <stdio.h>  
			 /* A review of the loop types in C. */
int main()
{
int i,x;

x=0;
for (i=0; i<4; i++)
  {
  x=x+i;
  printf("%d\n",x);
  }
while (i<7)
  {
  x=x+i;
  i++;
  printf("%d\n",x);
  }
do
  {
  x=x+i;
  i++;
  printf("%d\n",x);
  }
while (i<9);
}