Question:What type of inheritance that PHP supports?

 

PHP does not support multiple inheritances. PHP generally supports single type of inheritance.

Question:What is constant? How can you declare a constant?

 

Ans: Constant is a value that cannot be modified throughout the execution of a program.Constant are declared by using define () function.

Question:What is the difference between print and printf? 

Ans: The difference of print and printf are as the print statement is used output data passed to it, but the printf statement is used t output a blend of statement and dynamic information stored within one or several variable.

Question:Difference between array_merge() and array_slice()?  

Ans: The array_merge() function merges one or more arrays into one array. This function returns one array with the elements of all the parameter arrays.

The array_slice() function returns selected parts of an array. The array_slice() function returns part of an array as specified by the start and length parameters. If start is a positive number, it means that the ”slice” will start that many elements from the beginning of the array.

Question:What are the abstract class and interface?

 

Abstract class: An Abstract. Class is a class that cannot be instantiated but instead serves as a base class to be inherited by other classes.
Interface: An Interfaces is a collection of unimplemented method definitions and constantswithout specifying exactly how it must be implemented.

Question:Define exceptions? 

 

An exception is an abnormal condition that arises in a code sequence at run time. Basically there are four important keywords which form the main pillars of exception handling: try, catch, throw and finally. 

Question:What is regular expression?

 

Regular expressions provide the foundation for describing or matching data according to defined  syntax rules. Generelly regular expressions declared by "/^[value]{range}$/";.

Question:How many ways you can read a file?

 

We can read a file using the following mode and Methods:-
Methods- file(), file_get_contents(), fgetcsv(), fgets(), fgetss(), fgetc(),fresd(), readfile(), fscanf().  
Mode-  R, r+, w+, a+, x+

Question:Why substr() is used? 

Ans:  The substr() function is used to return the part of a string located between a predefined starting offset and length position.
Its prototype follows:
string substr(string str, int start [, int length])

Question:How many ways you can write into a file?

 

We can write into a file using the following mode and Methods:
Methods- fwrite() with fopen, file_put_contants().   
Mode-  r+,  W,  w+, A, a+, X, x+