Write a C Program to display reverse and length of string using Recursion

Recursion : :

• Recursion is the process of repeating items in a self-similar way. In programming languages, if a program allows you to call a function inside the same function, then it is called a recursive call of the function.

• The C programming language supports recursion, i.e., a function to call itself. But while using recursion, programmers need to be careful to define an exit condition from the function, otherwise it will go into an infinite loop.

• Recursive functions are very useful to solve many mathematical problems, such as calculating the factorial of a number, generating Fibonacci series, etc.

Below is the source code for C Program to display reverse and length of string using Recursion which is successfully compiled and run on Windows System to produce desired output as shown below :

SOURCE CODE : :

/* C Program to display reverse and length of string using Recursion */


#include<stdio.h>
#include<string.h>
void display(char *str);
void Rdisplay(char *str);
int length(char *str);

int main( )
{
        char str[100];
        printf("Enter a string : ");
        gets(str);

        printf("\nOriginal string : ");
        display( str );
        printf("\n");
        printf("\nReverse string : ");
        Rdisplay(str);
        printf("\n");
        printf("\nLength of a string : ");
        printf("%d\n",length(str));

        return 0;

}/*End of main()*/

void display(char *str )
{
        if(*str == '\0')
              return;
        putchar(*str );
        display(str+1);
}/*End of display()*/

void Rdisplay(char *str )
{
        if(*str == '\0')
              return;
        Rdisplay(str+1);
        putchar(*str );
}/*End of Rdisplay()*/

int length(char *str )
{
        if(*str == '\0')
              return 0;
        return (1 + length(str+1));
}/*End of length()*/

OUTPUT  : :

***************OUTPUT***************


***************FIRST RUN************

Enter a string : Hello World

Original string : Hello World

Reverse string : dlroW olleH

Length of a string : 11


***************SECOND RUN************

Enter a string : Codezclub

Original string : Codezclub

Reverse string : bulczedoC

Length of a string : 9