The while loop works as follows:
{
while( [expression is true] ) {
//Do this code
}
}
The while loop re-runs until the expression contained within the parentheses is false. Take a look at this example:
{
while(!place_meeting(x,y,obj_ground)) {
y += 1;
}
}
This while loop tells the object to move down one pixel until it collides with obj_ground. Unfortunately, nothing guarantees that this loop will not run forever. Always make sure that when you construct a while loop that you make sure that it does not run forever. Take a look at this whileloop:
{
while(obj_ball.y < y) {
draw_sprite(sprite_index,0,x,y);
}
}
This while loop will run for ever. Why? It does not have any statements that insure that the while loop aborts. Again, Always make sure that when you construct a loop that you put statements in the loop that will eventually abort the loop. y -= 1; is the statement in this new while loop that eventually aborts the loop:
{
while(obj_ball.y < y) {
draw_sprite(sprite_index,0,x,y); y -= 1;
}
}
FOR loops work as follows:{for( [initialize a variable]; [expression]; [increment the variable] ) {//Do this code}}Here as an example of a FOR loop:{for(i = 1; i < 10; i += 1) {show_message(string(i));}}What this will do is show a message 10 times displaying the value of "i" so you would get a message that says "1," another one after that saying "2," etc... The way this works is that you have the variable "i" initialized in the FOR loop. The FOR loop will keep looping until i >= 10, because the middle statement dictates that i must be smaller than 10 for the FOR loop activate. The third statement in the for loop is the statement that you increment the i variable with. If you change i += 1 to i -= 1 then the FOR loop would go on forever, freezing the game. This is a critical mistake to make when constructing a FOR loop (as is with any loop.)
while, do...while, for, foreach are used
While--wend statement is used to execute a loop until a given condition is true.if the condition is false the loop ends and the program continous to the line following eend.
simple code example: <? while ($a < 10 ) { echo "$a, "; $a++; } echo "Finished"; ?> Will output, 1, 2, 3, 4, 5, 6, 7, 8, 9, Finished this will run through the loop WHILE $a is less than 10, outputting the value of $a to the screen. once $a = 10 then the loop will end and continue on with the rest of the script
An infinite loop.
In any programming language, a "while" loop and a "do until" loop are the same except for 1 difference. In order to enter a while loop, the condition must always be true. But in a do until loop, if the condition was false, the block of code inside the loop will always be ran at least once. Example: while (false) { // code here } in this example, the code inside the while loop will never run, but in the following example: do { //code here } until(false) although the condition is false, the code will be run 1 single time and the exists the loop.
A nested loop is a (inner) loop that appears in the loop body of another (outer) loop. The inner or outer loop can be any type: while, do while, or for. For example, the inner loop can be a while loop while an outer loop can be a for loop.
They both loop
FOR loops work as follows:{for( [initialize a variable]; [expression]; [increment the variable] ) {//Do this code}}Here as an example of a FOR loop:{for(i = 1; i < 10; i += 1) {show_message(string(i));}}What this will do is show a message 10 times displaying the value of "i" so you would get a message that says "1," another one after that saying "2," etc... The way this works is that you have the variable "i" initialized in the FOR loop. The FOR loop will keep looping until i >= 10, because the middle statement dictates that i must be smaller than 10 for the FOR loop activate. The third statement in the for loop is the statement that you increment the i variable with. If you change i += 1 to i -= 1 then the FOR loop would go on forever, freezing the game. This is a critical mistake to make when constructing a FOR loop (as is with any loop.)
A Do-While loop looks like this: do { loop body } while (condition); and a While loop looks like this: while (condition) { loop body } The main difference is that the loop body is always run once in the Do-While loop, then the condition is checked to see if the loop should keep running. In a While loop, the condition is checked first, and it will not run the loop body at all if the condition is false.
Is loop
A while loop repeats until the condition becomes false, and may never execute: int a = 4; while (a > 5) { //Do something } or int a = 4; while (a > 0) { //Do something a--; }
A Loop is a programming language construct that instructs the processor to repeat a sequence of operations a number of times until a specific condition is reached. There are different types of loops. They are: * for loop * while loop * do while loop
There are 3 type of loop 1 is for loop 2 is loop while 3 is loop untile
We need a for loop because the while and do-while loops do not make use of a control variable. Although you can implement a counter inside a while or do-while loop, the use of a control variable is not as self-evident as it is in a for loop. Aside from the use of a control variable, a for loop is largely the same as a while loop. However, it is quite different to a do-while loop, which always executes at least one iteration of the loop before evaluating the conditional expression. In a for and while loop, the conditional expression is always evaluated before entering the loop, which may result in the loop not executing at all.
The contents of a while loop will always execute if the statement between the while parentheses resolves to a boolean true. Hence, if you place "true" as the while statement, the loop will execute forever (until the loop is forcefully broken or the computer or process shuts down).
A for loop is classified as an iteration statement. A simple example might be... For x = 1 To 10 'loop body Next x The same loop expressed as a while loop (classified as a control flow statement) could be... x = 0 Do While x < 11 'loop body x = x + 1 Loop .