This document discusses while loops and how to properly structure them. It explains that a while loop will repeat a set of instructions as long as a condition is true. It advises that the variable checked in the condition must be initialized before the loop and able to change inside the loop. The document also covers incrementing and decrementing as tools for iterating through loops, noting the differences between pre-increment, post-increment, and other shorthand forms.

1. CS111 Lab
while loops
Instructor: Michael Gordon

2. Repeating instructions
 To repeat a set of instructions, we can use
a while loop, which checks a condition
(like an if statement) and continues as
long as the condition is true.
 while (condition to check){
instructions;
}

3. A word of advice
 If the while loop checks a certain variable,
make sure that:
 A) The variable has a value before the loop
starts.
 B) That variable can change inside the loop.
 x = 1;
 while (x<5){“output”} will never end
 while (x<5) {x++; “output”} will stop once x is 5.

4. Incrementing
 Incrementing (+1) and decrementing (-1)
are useful tools for iterating in loops.
 int x = 0;
 x++; //means x = x+1; called post-increment
 ++x; // means x = x+1; called pre-increment
 x+=1; // means x = x+1;
 Decrementing:
 --x;
 x--;