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PHP find output programs (User-defined functions) | set 1

Find the output of PHP programs | User-defined functions | Set 1: Enhance the knowledge of PHP User-defined functions concepts by solving and finding the output of some PHP programs.
Submitted by Nidhi, on January 22, 2021

Question 1:

<?php
    function fun()
    {
        printf("Hello World");
    }
    echo ("Hello India");
?>

Output:

Hello India

Explanation:

In the above program, we defined a user-define function. But we did not call function fun() anywhere then it will not print "Hello World", only "Hello India" will print on the webpage.

Question 2:

<?php
    fun();
    
    function fun()
    {
        printf("Hello World<br>");
    }
    
    echo ("Hello India");
?>

Output:

Hello World
Hello India

Explanation:

In the above program, we defined a user define function. Then we called function fun() then it will print "Hello World", and  "Hello India" will print on the webpage.

Question 3:

<?php
    $A = 5;
    $B = 10;
    
    fun($A, $B);
    printf("%d, %d", $A, $B);
    
    function fun(int $A, int $B)
    {
        $A = 20;
        $B = 30;
    }
?>

Output:

5, 10

Explanation:

In the above program, we defined a user define function fun() that contains two parameters $A and $B. We modified the values of $A and $B, but it will not reflect at the calling position. Because here we used the call by value mechanism for parameter passing. Then "5,10" will be printed on the webpage.

Question 4:

<?php
    $A = 5;
    $B = 10;
    
    fun(&$A, &$B);
    printf("%d, %d", $A, $B);
    
    function fun(int $A, int $B)
    {
        $A = 20;
        $B = 30;
    }
?>

Output:

PHP Parse error:  syntax error, unexpected '&' in 
/home/main.php on line 5

Explanation:

The above program will generate syntax error because we cannot use ampersand '&' operator in the function call. To implement call by reference mechanism for parameter passing. We need to use ampersand '&' operator in the function definition.

Question 5:

<?php
    $A = 5;
    $B = 10;
    
    fun($A, $B);
    printf("%d, %d", $A, $B);
    
    function fun(int & $A, int & $B)
    {
        $A = 20;
        $B = 30;
    }
?>

Output:

20, 30

Explanation:

In the above program, we defined a user define function fun() that contains two parameters $A and $B. We modified the values of $A and $B, but it will also reflect at calling position. Because here we used the call by reference mechanism for parameter passing. Then "20,30" will be printed on the webpage.

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