REVERSE NUMBER AND STRING

21)C PROGRAM TO REVERSE A NUMBER AND A STRING

(A)REVERSE A NUMBER

LOGIC:-

take any number from user which you want to reverse
using "/" to find the quotient i.e let num=2351 now divide num/10 = 235.Next using "%" to find the remainder i.e num%10=1 store it.
again divide the new num which is 235 now we have new num after divide is =23 and remainder is 5. so apply logic that after 1 , 5 is come and so on...
reverse=reverse*10+remainder // this code create a reverse.

EXAMPLE:-

(B)REVERSE A STRING:

LOGIC:- we can reverse string from many ways by using string reverse function(strrev()), without strrev() , by using pointers etc.Here 2 ways are given.

EXAMPLE 1 :- BY USING STRREV FUNCTION

EXAMPLE 2 :- WITHOUT USING STRREV FUNCTION

first declare two empty character array(similar to string).
input string in one array
now find the length of the input array.
now using a loop where first character of input array is insert at the last of second array and so on
now we have a reverse of the string

NOTE:- WE ALSO FIND THE LENGTH OF STRING USING FUNCTION STRLEN().

(C)BY USING RECURSION:

LOGIC:- Recursion means a function call itself.So we create a function which call itself.In this function we write the code to reverse the string

EXAMPLE:-

TASK:"""TRY WITH POINTER""" WHERE YOU CAN USE SWAPPING TECHNIQUE

Comments

Type casting

type casting or type conversion allows us to convert one data types into another.for type casting cast operator is required. Syntax:-- (type)expression or value; Example: int f =9/4; //without type casting o/p=2 float f=(float)9/4; //with type casting o/p=2.3 Type conversion are of two types: 1)Implicit Type Conversion:- it is also known as automatic type conversion.When the type conversion is performed automatically by the compiler,such type of conversion is known as implicit type conversion. 2)Explicit Type Conversion:- the type conversion performed by the programmer is known as explicit type conversion.which is done by cast operator as above mentioned.

Introduction to C

About C:- C is a high-level language . It was initially first developed by D ennis Ritchie in 1972. It was developed to overcome the limitation of previous language such as B,BCPL etc. It was developed for Unix operating System It inherits many features of previous language Features/Advantage:- Simple :- because it provide data types, library function etc. Machine Independent or Portable:- because it can be executed on different machine Procedural language:- Instruction in c program are executed step by step Structured programming language:- break the problem into parts It provide dynamic memory allocation , pointers etc. Speed:-It is faster than another programming language like java, python etc. Disadvantage of C:- It does not support oops concept in which inheritance, polymorphism, encapsulation etc. come. It does not support namespace concept It does not support constructor and destructor There is lack of excepti...

Recursion--

Definition:- when a function call itself is called recursion. note:- the problem which is solved by recursion is also solved by loops, but it is not necessary the problem solved by loops is also solved by recursion. Example:- Explanation:- 1) a fun function declared which takes argument and return value 2) main starts fun is called by passing 3 value 3)after calling fun definition starts, where check if a==1 no because a is 3, s=a+fun(a-1) means s=3+fun(2) from here fun function is again called now this body again execute now a is 2, so s=3+fun(2), fun(2) is replaced by 2+fun(2-1=1) i.e s=3+2+fun(1) again fun function is called... overall s=3+2+1=6, s is return this return value goes where fun function is called , where return value is stored in k, so k=6 now print is 6.

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