Looping Statements

Looping statements allow a block of statements to be repeated 0 or more times depending upon a certain condition.

While loops
while (conditional expression) { code to execute;  // Must contain a statement that switches the condition from TRUE to FALSE }

// Example $n = 1; while ($n <= 10) { echo "n equals $n "; $n++;                 // Eventually $n will be greater than 10 and the loop stops. } echo "Done";

Do-while loops
In the do-while loop the condition occurs after the statement block so the block is executed at least once. do { code to execute; } while (conditional expression);

// Example $n = 1;     // Loop initialization do { echo "n equals $n "; $n++;                 // Loop Modification: Eventually $n will be greater than 10 and the loop stops. } while ($n <= 10);  // Loop Condition echo "Done";

For loops
The for loop provides the same functionality as the while and do-while loop but puts everything together into a single statement: for (initialization expression; conditional expression; modification expression) { code that is executed; }

// Example for ($n=1; $n <= 10; $n++) { echo "n equals $n"; }

Homework problem 4-13
Write a PHP script that contains a for loop that prints the values from 0 to n that are divisible by m. For example if n is 20 and m is 3, then your loop should print: 0, 3, 6, 9, 12, 15, 18. If m were 5, it should print 0, 5, 10, 15, 20. Click here for a solution.