while
 while(TRUE) {
  do something
};
Example:
#include <iostream.h>
int main()
{
int x=0;
while (x<100)
{
cout << x << endl;
x++;
}
return 0;
}
The basic structure is...WHILE(true) then execute all the code in the loop. The true represents a boolean expression which could be x==1 or while(x!=7) (x does not equal 7). It can be any combination of boolean statements that are legal. Even, (while x==5 || v==7) which says execute the code while x equals five or while v equals 7.
Comment to example:
1.Don't forget to declare variables
2.While x is less than 100 do
3. x++; Adds 1 to x every time it repeats, in for loops the loop structure allows this to be done in the structure