Loops
Contents
An Introduction
A loop is a control structure that repeatedly executes a sequence of steps for as long as a test condition evaluates to true. What does iterate mean?
Types of Loops
- while
- for -Roger
- nested loops -Roger
Test Condition
Loops use the test condition to decide whether or not to enter the body of the loop.
Scope
Everything within the body of the loop is considered to be in the scope of the loop. In the case of a for loop, any variable declared in the inializer is considered to be within the scope of the loop. Declaring a variable within the variable within the scope of a loop is highly discouraged. This variable would be difined again everything time the loop iterates, causing a significant waste of memory.
Infinite Loops
An infinite loop is any loop that continues to repeat forever. There are situations where this is useful, but if you didn't intentionally program it in, then it causes a fatal error for your program. These occur if the test condition in your loop will never be false. Here are a few examples of infinite loops:
while(true) //always true
{
}
------------------------------------------------
for(int i = 0; i < 20; i++) //counter reset to 0 every time
{
i = 0;
}
------------------------------------------------
for(int i = 0; i < 5e9; i++) //integers can't be as big as 5e9(5*10^9), so i will overflow to negative
{
}
