Controlling Program Flow In Php

In this write up we would learn to use a conditional statement like if statement, and if-else statement. Further we would learn about common comparison operators and the ternary operator. In this write up we would learn about more intelligent PHP programming which deals with modern programming involves minimization of code with optimization results.

PHP programs are pretty straight forward coding language. Unlike other programming code which includes multiple stages of executions, it requires a simple HTML based web browser to execute edited codes. PHP programming is based on programmer-specific conditions where complex decisions on simple programs need to be taken. PHP has certain built-in functions which are intelligent in nature and automatically detect actions and loops to perform complex operations easily.

Variables functions within PHP are best as values could be stored and managed within set of variables. PHP provides an added advantage to programmers to take stock of conditions and add an additional set of rules before proper execution of codes. Conditional statement exists within a PHP program which lets programmers take stock of program execution, and create certain construct which are intended for a particular use.

There are many compound conditional statements which are used inside PHP statements. Easiest form conditional statement is ‘if’ statement.

‘If’ conditional statement is invariably used with variables.

 

Suppose at a certain point of programming which includes the building of a calculator, which would work within the HTML browser, you would want a condition where certain variable when it is less than needs to be identified among a different set of numerical variables.

<?php

$number = -88;

if ($number < 0) {

echo 'It is negative';

}

?>

In the above example, PHP tag begins ‘’with <?php and ends with ?> Within these specimens the if conditional statement exists. Here Number is variable as the dollar sign is before it and it is equal to minus 88 and that line ends with a semicolon (;). In the next sentence begins ‘If’ statement and within braces the condition is if the variable number is less than zero than echo it means printing it as ‘it is negative’.  It is simple at the first line variable number is used and aptly followed by ‘if statement’ with a condition attached with that number should be less than zero and if the above number attached with variable is less than zero then execution part is it is negative.

What is the key part of this example? From the above example, it is aptly clear that, when ‘if statement’ is used it is used for evaluation of the condition. That condition of ‘if statement’ is always enclosed in parentheseses. Here the condition of ‘if statement’ is ($number < 0).

Conditional programming such as above discussed ‘if statements’ are examples of controlling programming languages. It gives greater control of execution of codes to programmers. If-else statement is an improved version over if statement and it specifies an alternative set of actions for if statements when a given condition under if the statement happens to be false. In this way, once program is executed there is a lesser chance of returning false due to alternative else statements in if-else constructs.

If-else statements provide small and convenient codes and these codes become more readable within construction parameters.

 

If-else statement combines two actions into one constructible action. If-else statement is an extension over If statement which specifies once the code is executed remain executed and no false return policy of execution construction would be possible. Here is an example of If-else statement which is addition over the previous executable If statement.

<?php

$number = -88;

if ($number < 0) {

echo 'It is negative';

} else {

echo 'It is either positive or zero';

}

?>

PHP code begins and ends with its parameter such as <?php and ?> Then part up to If the statement is well understood in previous detailed illustrations. Now we would be moving towards else statement part where it is significant to note that an else statement begins after end of curly braces of if statement and no semi-colon (;) is used here. This means, continuance of if statement and then it is written else and then begins with curly braces and then echoes means execution and within single quote it is written that it is either positive or zero. After it comes the end of curly brace of else statement.

It is significant within If-else statement, conditions regarding evaluation of if statement comes first if it comes false then revert back to else statement of function which then regards that number is not negative then it should be either positive or zero. Here, if-else statement is used to ascertain about two possible outcomes. While executing this code, you could change the variable to positive to see the execution part and this time you would find exactly the execution of else statement in programming action.

Prima facie from the front end coding of if-else conditional statement it looks like code size increases and there are some built-in programming operators within PHP. As we discussed above such built-in operators within PHP make this complex coding system easier for programmers. Also due to internet bandwidth involves while execution of such codes it is always a good idea to keep code clean and compact. Here, is an example of a ternary operator which is represented by the question mark (?) which removes all clusters of a conditional statement and keep it short and simple (kiss) and found it within a shortest possible area.

 

<?php

echo ($number< 0) ? 'It is negative’: 'It is either positive or zero'

?>

Here ternary operator (?) is used and it relates with code on its left that is about ‘echo ($number< 0)’ and if it is true then the execution part comes just next to ternary operator and if comes false, then codes on right is executed. It removes an extra bit of programming of if-else conditional statement coding.

This program consists of two parts and the first half is on the left side of the ternary operator and the second part is after the colon. When the required number is less than zero then there is no need for execution of the second part just after colon (:).  If it satisfies general if condition then it comes out with an appropriate message and there is no further need for an else statement. Where as if the constraint on left does not satisfy with the condition of if statement then it comes to else statements on right which justly create appropriate conditions of a PHP script.

The basic question is how does it work? When the web form is submitted by the user in the magic script created by conditional statement the intended entry comes in submitting a statement of PHP programming. If the first statement returns with false statement then it goes into second relevant else statement and relevant else statement should be done in such manner so that the return execution of a conditional statement must adhere to else statement policy of programming code.

This article clearly shows how testing of input value of the statement is examined through various processes of value inputs were complete execution of conditional statements comes into light. If it returns true then the message on the left side comes into light otherwise the information written on the right side is executed.


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  • sumitdgr9  13-03-2015

    this is really technical one and nice infomation on use of else and if else in coding of programming.

    reply 0