What is the use of mysqli_real_escape_string() function?

mysqli_real_escape_string() function is used to escape special characters from the string for using a SQL statement

$DBconnection = mysqli_connect("localhost","username","dbname");
$productName = mysqli_real_escape_string($con,$_POST['proname']);
$ProductType = mysqli_real_escape_string($con,$_POST['protype']);

How will you calculate days between two dates in PHP?

Calculating days between two dates in PHP

$date1 = date("Y-m-d");
$date2 = "2015-10-02";
$days = ( strtotime($date1) - strtotime($date1))/(60*60*24);
echo $days;

Which operator is used to combine string values in PHP?

Two or more string values can be combined by using ‘.’ operator.

$val1 = "Software ";

$val2 = "Testing";

echo $val1.$val2; // The output is “Software Testing”

How is a constant defined in a PHP script?

Defining a Constant in PHP

define('CONSTANT_NAME',value);

How to get length of an array in PHP ?

PHP count function is used to get the length or numbers of elements in an array

<?php
// initializing an array in PHP
$array=['a','b','c'];
// Outputs 3 
echo count($array);
?>

The value of the variable input is a string 1,2,3,4,5,6,7. How would you get the sum of the integers contained inside input?

<?php
echo array_sum(explode(',',$input));
?>

What is cURL in PHP ?

cURL is a library in PHP that allows you to make HTTP requests from the server.

What is the difference between “= =” and “= = =” operators.

“= = =” is called strictly equivalent operator that is used to check the equivalency of two values by comparing both data types and values.

Ex : 10 and “10” are equal by values but are not equal by data type. One is a string and one is a number. So, if the condition will be false and print “n is not equal to 10”.

$n = 10;

if ($n === "10")

echo "n is equal to 10";

else

echo "n is not equal to 10"; //This will print

Which function you can use in PHP to open a file for reading or writing or for both?

You can use fopen() function to read or write or for doing both in PHP.

$file1 = fopen("myfile1.txt","r"); //Open for reading

$file2 = fopen("myfile2.txt","w"); //Open for writing

$file3 = fopen("myfile3.txt","r+"); //Open for reading and writing

Can you extend a Final defined class?

No, you cannot extend a Final defined class. A Final class or method declaration prevents child class or method overriding..