While Loop

Do While Loop 

 #include<iostream.h>

#include<conio.h>

void main (){

int i=0,a=0;

clrscr();

cout<<"Enter -";

cin>>i;

while(i>=0)

{

a=a+i;

 cout<<"Enter Num - ";

 cin>>i;

}

cout<<"Sum = "<<a;

getch();

}