Built-in-Functions (String) – Enjoy it!

Let us plunge to another episode of functions, I know it is boring; at the same time it is most handy when you want to finish a program with lots of mathematical formula. Last week I have gone through a few numerical functions and the way functions help us for converting one data type to other. Today mainly I will discuss about string function, which only valid to string type data. String handling is not an easy job and you will find many functions available for this, but often while you write a program, you will be asked to write your own functions only and prohibited from using some of the string function. So, how to do this I will come to this when we talk about programming. String functions in Java return value is string but some return integer also. In java java.lang is default package so you do not need any extra package to be import but in C/C++ you require "string.h".

Note : Str - is the String argument you have to pass and Num is a Number of character and pos is the position.

Description	Basic	C/C++	Java
Find the length of a string value	len(Str$)	strlen(Str)	Str.length()
Extract a character from the said string from given position	mid$(Str$,pos,num)	str(pos)	Str.charAt(pos)
Check equality between two string and return a Boolean value/			Str1.equals(Stri2)
Check equality between two string ignoring he case difference and return a Boolean value.			Str1.equalsIgnorecase(Str2)
Compare between two string( relevant to the ASCII values of each character), if both equal it return 0, if String1 is smaller than String2 then it will return -1 and if String1 is bigger than String2 then it will return 1.		strcmp(Str1,Str2) strcmpi(Str1,Str2) (strcmpi() - for ignoring case)	Str1.compareTo(Str2)
Extract all the string from given position till end.			String.substring(int)
Extract all the string from starting position up to left of end position.	mid$(Str$,pos,num) left$(Str$,num) right$(Str$,num)	Using any loop from 0 position till length of the string, we can extract character by character	Str1.substring(int,int) -
Join String2 to the right of String1	Str1$+Str2$	strcat(Str1,Str2)	Str1.concat(Str1) This can be done by: String1=String1+ String2.
Returns the index within this string of the first occurrence of the specified character.			Str.indexOf(char/string)
Returns the index within this string of the first occurrence of the specified character, starting the search at the specified index.			Str.indexOf(char/string, int)
Returns the index within this string of the last occurrence of the specified character.			Str.lastIndexof(char/String)
Tests if this string starts with the specified prefix.			Str.startswith(String)
Tests if this string ends with the specified suffix.			Str.endsWith(String)
Removes white space from both ends of this string.			Str.trim()
Returns a new string resulting from replacing all occurrences of oldChar in this string with newChar.			Str.replace(char, char) Str.replace(Str1, Str2)
Converts this String to lowercase / Converts this String to upper case.		strlwr(Str) / strupr(Str)	Str.toLowerCase() / Str.toUpperCase()
Converts this string to a new character array.			Str.toCharArray()

In java we also having StringBuffer, so giving you some idea of this class-

A string buffer implements a changeable sequence of characters. String buffers are safe for use by multiple threads. The methods are
synchronized where necessary so that all the operations on any particular
instance behave as if they occur in some serial order. String buffers are used by the compiler to
implement the binary string concatenation operator +. For example, the code:

x = "a" + "4" +"c";

is compiled to the equivalent of:

x = new StringBuffer().append("a").append(4).append("c").toString()

Functions under StringBuffer

Description	Java
Constructs a string buffer with no characters in it and an initial capacity specified by the length argument.	StringBuffer()
Constructs a string buffer with no characters in it and an initial capacity of 16 characters.	StringBuffer(int)
Constructs a string buffer so that it represents the same sequence of characters as the string argument.	StringBuffer(String)
Appends the string representation of the boolean argument to the string buffer.	append(boolean)
Appends the string representation of the char argument to this string buffer.	append(char)
Appends the string representation of the char array argument to this string buffer.	append(char[])
Appends the string representation of a subarray of the char array argument to this string buffer.	append(char[], int, int)
Appends the string representation of the int, float or double argument to this string buffer.	append(int) /append(float) /append(double)
Returns the current capacity of the String buffer.	capacity()
Returns the character at a specific index in this string buffer.	charAt(int)
Inserts the string representation of the char argument into this string buffer.	insert(int, char) **
Inserts the string representation of the char array argument into this string buffer.	insert(int, char[])
Returns the length (character count) of this string buffer.	length()
Characters are copied from this string buffer into the destination character array.	getChars(int, int, char[], int)
Sets the length of this String buffer.	setLength(int)
The character at the specified index of this string buffer is set to ch.	setCharAt(int, char)
The character sequence contained in this string buffer is replaced by the reverse of the sequence.	reverse()
Converts to a string representing the data in this string buffer.	toString()

** Insert can be used as append for numeric too.

Here is a example, how we can use string buffer

System.out.println("StringBuffer insert and append example!");

StringBuffer sb = new StringBuffer(0);

System.out.println(sb.insert(0, "vinod"));

int len = sb.length();

System.out.println(sb.insert(len, "Deepak"));

System.out.println(sb.insert(6, "Raj"));

System.out.println(sb.append("Mohit"));



Database packages also provide some date and database functions, while writing about database I certainly cover those functions. I also remind you that if you feel anything left out then can suggest me, your suggestion will be always welcome.

!!!I know most of the students are busy with their respective examination and hardly have time to join this function, so Aburz for all.!!!

Built-in-Functions (Maths) – Enjoy it!

Readymade with zero price tag and unlimited access, that is how I can describe a built-in-function. All programming languages having certain amount of built-in-function, which written as subroutine or function to solve a certain requirement, while writing a program you can, call these functions by sending arguments that required or with no arguments.

It is not that we cannot solve these, but when it is available, we just use it. Built-in-functions come in different types depending upon data types – Numeric, Date, String, Database etc. I will cover this topic in two weeks and with a few which we use frequently.

Numeric or math function to solve a mathematic routine like square root and other. Many math functions in Java return value is double type but you can take help of  type casting to get it in integer. In java java.lang is default package so you do not need any extra package to be import but in C or C++, you have to include "math.h" but for min() and max() in C/C++ you require
"stdlib.h" or often "complex.h"

Note : Num - is the numeric argument you have to pass.

Description	Basic	C & C++	Java
Returns the square root of a double value.	sqr(num)	sqrt(num)	Math.sqrt(num)
Returns the absolute value of a double value.	abs(num)	abs(num)	Math.abs(num)
Returns of value of the first argument raised to the power of the second argument.		pow(num,num)	Math.pow(num,num)
Returns the smaller of two Numeric values.		min(num,num)	Math.min(num,num)
Returns the larger of two Numeric values.		max(num,num)	Math.max(num,num)
Returns the trigonometric sine, cosine and tangent of an angle where argument should be in radian.	sin(num) cos(num) tan(num)	sin(num) cos(num) tan(num)	Math.sin(num) Math.cos(num) Math.tan(num)
Returns the exponential number  (i.e., 2.718...) raised to the power of a double value.	exp(num)	exp(num)	Math.exp(num)
Returns the smallest (closest to negative infinity) double value that is not less than the argument and is equal to a mathematical integer.  ceil(12.5) = 13, ceil(-12.5) = -12	cint(num)	ceil(num)	Math.ceil(num)
Returns the largest (closest to positive infinity) double value that is not greater than the argument and is equal to a mathematical integer. floor(12.5) = 12, floor(-12.5) = -13.	fix(num)	floor(num)	Math.floor(num)
Returns a random number between 0.0 and 1.0	rnd(num)	random()	Math.random()
Return a double number that represents the closest integer to the double parameter. rint(2323.43) =23.0, rint(2323.83) =23.0

Conversion - while writing a program we often have to change a data type to another. In C/C++, you need to include "stdlib.h". Here some example

Description	Basic	C & C++	Java
Integer to String	str$(num)	itoa(num,string,10) *	Integer.toString(num)
float to String	- do -	fcvt(num,ndigit,&dec,&sign)	Float.toString(num)
double to String	- do -		Double.toString(num)
String to Integer	val(string)		Integer.parseInt(String)
String to Float	- do -		Float.parseInt(String)
String to Double	- do -		Double.parseInt(String)

* 10 is the radix or base value, indicate that String value should be converted in Decimal. Binary (2), Octal (8) and in Hexadecimal (16).

Now these days Fortran and Pascal can be seen anywhere in the scenario, but some engineering Colleges having Fortran in their 3rd semester, so few Mathematical function for these programming languages are given below :

Description	Fortran	Pascal
Returns the square root of a double value.	sqrt(num)	sqrt(num)
Returns the absolute value of a double value.	abs(num)	abs(num)
Returns of value of the first argument raised to the power of the second argument.		sqr(num,num)
Returns the trigonometric sine, cosine and tangent of an angle where argument should be in radian.	sin(num) cos(num) tan(num)	sin(num) cos(num) tan(num)
Returns the exponential number  (i.e., 2.718...) raised to the power of a double value.	exp(num)	exp(num)
This returns a real number whose value is the integer part of the real value x. For example, Int(8.3), give you 8	int(num)	Int(num)
Modulus eg. mod(8,5) will give you remainder 3.	mod(num,num)

Next week coming with String functions. One thing I like to tell you, I often write my own packages for certain things and call my home made built-in functions, as I always like the challenge, but give you a tip too -

!!!Do not take too many challenges while appearing for exam, as exam itself is too challenging, happy finally time to say you Allez ciao!!!