The ability of someone when making a c++ programming will decrease if there is no loop structure. So it is not surprised if loop structure and if structure always used together in c++ programming. For that background, we write this tutorial about loop group structure.
For Structure
This structure will work based on an
increment or decrement. This structure very effective for prevent in writing the same statements.
Especially,
if contain so many same statements.
for
(variable_name=initial_value;condition;increment){
statement;
}
See
the example below
The program above will writing words i with
it values from one until five, where the increment of this program is one. This
fact can be seen from i++ statement (see our explanation).
While Structure
This structure will do looping based on a condition.
If the condition is true then it will do looping. For general, this structure will has form as
follow
Variable_name =
initial_value;
While (condition) {
Statement;
Variable_name++;
}
See
the simple example below
The result of this program is same with the result from the first program. From this program we can see that the initial value is one, but the condition is true if i less than or equal with five. It is mean the initial value is under that condition. So that the while structure will do looping. One thing you must notice, if you using while loop then you must add i++ increment (or other increment), if you don’t do it this then your program will not stop.
Do ... While Structure
The different between this structure with while structure is, this structure will do checking on the last term of the condition. And the while structure will do checking on the first term of the condition. The general form for this structure is
Variable_name = initial_value;
do {
statement loop;
Variable_name++;
} while (condition);
See the example below
The result of this program is same as before.
I want to add another difference between while and do-while...
ReplyDeleteThe contents of do-while is executed at least once, while the contents of while maybe executed at least once and maybe never been executed, depends on the initial check of condition.
[code]
int n = -1;
while (n > 0) {
cout << n << endl;
--n;
}
[/code]
will print nothing. but:
[code]
int n = -1;
do {
cout << n << endl;
--n;
} while (n > 0);
[/code]
will print:
-1
For Muhammad Alvin:
DeleteThanks. This good for others. We like this add, very basic, so the readers more understand between while and do-while.
When using for (initial; condition; increment), you are not forced to use all the 3 parameters. You can for example write for (;;) that is equivalent with while (true).
ReplyDeleteWhat you have to know when using for (initial; condition; increment) is the control flow. The basic form of for is:
for (_initial_; _condition_; _increment_) {
_body_
}
and it is equivalent with:
_initial_
while (_condition_ is true) {
_body_
_increment_
}
Try to write the following code:
for (int i = 1; i <= 10; i++) {
cout << i << endl;
}
then compare the result with the following code:
int i = 1;
while (i <= 10) {
cout << i << endl;
i++;
}
For Muhammad Alvin:
DeleteThanks for your share. If we do that in this post, then we never explain step by step to others. We hope you can understand for that. On the next future, we will make it, so the readers can understand the different and when they must using both.