Control Statements
Some statements serve to control the process of the program.
All control statements can be grouped into the following categories:
Conditional Statements
These statements serve to branch out the process of the program.
If Statement
On the basis of the Condition value this
statement decides whether the Statement should
be executed. If the Condition is true,
Statement is executed. If it is false, the
Statement is ignored and process continues next
after the if statement.
Statement is either simple statement or a block
of statements
if (Condition) Statement
Unlike the previous version of the if statement (in which the Statementis
executed only if the Condition is true), other
Statements that should be executed even if the
Condition value is false can be added to the
if statement. Thus, if the
Condition is true,
Statement1 is executed, if it is false,
Statement2 is executed. See below:
if (Condition) Statement1 else Statement2
The Statement2 can even be another
if statement and also with
else branch:
if (Condition1) Statement1 else if (Condition2) Statement3 else Statement4
Switch Statement
Sometimes you would have very complicated statement if you
created the statement of more branched out if statement.
In such a case, much more better is to use
the switch statement.
Now, instead of the Condition as in the if statement with only two values (true or false),
an Expression is evaluated and
its value is compared with the Constants specified in the switch statement.
Only the Constant that equals to the value of the Expression decides which of the Statements is executed.
If the Expression value is Constant1, the Statement1 will be executed, etc.
![[Important]](figures/important.png) | Important |
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Remember that literals must be unique in the |
switch (Expression) { case Constant1 : Statement1 StatementA [break;] case Constant2 : Statement2 StatementB [break;] ... case ConstantN : StatementN StatementW [break;] }
The optional break; statements ensure
that only the statements correspoding to a constant will be executed. Otherwise, all below them would be executed as well.
In the following case, even if the value of the
Expression does not equal to the values of the
Constant1,...,ConstantN,
the default statement (StatementN+1) is executed.
switch (Expression) { case Constant1 : Statement1 StatementA [break;] case Constant2 : Statement2 StatementB [break;] ... case ConstantN : StatementN StatementW [break;] default : StatementN+1 StatementZ }
Iteration Statements
These iteration statements repeat some processes during which
some inner Statements are executed cyclically
until the Condition that limits the execution
cycle becomes false or they are executed for all values of the same data type.
For Loop
First, the Initialization is set up, after that, the
Condition is evaluated and if its value is
true, the Statement is executed and finally the
Iteration is made.
During the next cycle of the loop, the
Condition is evaluated again and if it is true,
Statement is executed and
Iteration is made. This way the process repeats
until the Condition becomes false. Then the
loop is terminated and the process continues with the other part
of the program.
If the Condition is false at the
beginning, the process jumps over the Statement
out of the loop.
for (Initialization;Condition;Iteration) Statement
| Important |
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Remember that the
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Do-While Loop
First, the Statement is executed, then
the process depends on the value of Condition.
If its value is true, the Statement is executed
again and then the Condition is evaluated again
and the subprocess either continues (if it is true again) or stops
and jumps to the next or higher level subprocesses (if it is
false). Since the Condition is at the end of
the loop, even if it is false at the beginning of the subprocess,
the Statement is executed at least once.
do Statement while (Condition)
While Loop
This process depends on the value of
Condition. If its value is true, the
Statements is executed and then the
Condition is evaluated again and the subprocess
either continues (if it is true again) or stops and jumps to the
next or higher level subprocesses (if it is false). Since the
Condition is at the start of the loop, if it is
false at the beginning of the subprocess, the
Statements is not executed at all and the loop
is jumped over.
while (Condition) Statement
For-Each Loop
The foreach statement is executed on all fields of the same data type within a container. Its syntax is as follows:
foreach (<data type> myVariable : iterableVariable) Statement
All elements of the same data type (data type is declared in this statement) are searched in
the iterableVariable container. The iterableVariable can be a list, a map, or a record.
For each variable of the same data type, specified Statement is executed. It can be either a simple statement or a block of statements.
Thus, for example, the same Statement can be executed for all string fields of a record, etc.
Jump Statements
Sometimes you need to control the process in a different way
than by decision based on the Condition value. To
do that, you have the following options:
Break Statement
If you want to stop some subprocess, you can use the following statement in the program:
break;
The subprocess breaks and the process jumps to the higher
level or to the next Statements.
Continue Statement
If you want to stop some iteration subprocess, you can use the following statement in the program:
continue;
The subprocess breaks and the process jumps to the next iteration step.
Return Statement
In the functions you can use the return
word either alone or along with an expression.
(See the following two options below.) The return statement can be in any place within
the function. There may also be multiple return statements among which a specific one is executed
depending on a condition, etc.
return;
return expression;