C program String Reverse and palindrome

A array of characters enclosed by double quote and delimited by a NULL character is called string. The string is transformed into reverse string without using build-in function by this c programming given below.

                 
           char name[20] =  "dennis ritchie";
      

String Reverse

string reverse - read a character by character from last to first index and copy it into another character array and finally add NULL character (delimiter) at end of the string

 
                                  ------------ 
         "dennis ritchie" ---->   |  Reverse | --->  "eihctir sinned"
                                  ------------   
   

String Reverse - C programming code

The C program transform a given string into reverse string. The input string is to reverse read from user and prints reversed string as result of the program.

 
#include <stdio.h>
#include <string.h>

int main() {

  char str[20];
  char rstr[20];
  printf("\n Reverse a given string without using build-in function");
  printf("\n Enter a string :");
  scanf("%s",&str) ; 
 
 
  int len = strlen(str);
  for(int n=0;n<len;n++)
     rstr[len-1-n]=str[n];
  
  rstr[len] = '\0';
  
  printf("\n Reversed String : %s",rstr);
  return 0;
  
}

 

String Reverse - C programming output

 Reverse a given string without using build-in function
 Enter a string
  government
Reversed String
 tnemnrevog

It is a C program which verifies that the given string is palindrome or not without using build-in function string reverse.

palindrome

A string is a palindrome or not is found by comparing the string with reverse of the string itself. if the comparison result is true, the string is called palindrome otherwise the string is not palindrome.

 
                                  ------------ 
         "dennis ritchie" ---->   |  Reverse | ---->  "eihctir sinned"
                           |      ------------   |  
                           |                     |
                           |       ----------    |
                           |---->  | compare |<--|
                                   ----------
                                      |
                                      |
                               palindrome/ not    

   

Palindrome - C programming code

The C program transform a given string into reverse string and compare both the given string and reversed string are equal. The input string is read from user and prints the given string is palindrome or not as result of the program.

 

#include <stdio.h>
#include <string.h>

int main() {

  char str[20];  
  char rstr[20];
  
  printf("\n Finds a given string is Palindrome or not quot;);
  printf("\n Enter a string :");
  scanf("%s",&str) ; 
  
  int len = strlen(str);
  for(int n=0;n<len;n++)
     rstr[len-1-n]=str[n];  
  rstr[len] = '\0';
  
  
  if ( strcmp(str,rstr)==0 )
     {
     printf("\nThe string is Palindrome");
     printf ("\n %s",str );
     printf ("\n %s",rstr );
    }
  else {
      printf("\n The string  is not Palindrome");
 }
   
  return 0;
  
}

 

Palindrome - C programming output

 Finds a given string is Palindrome or not
 Enter a string
 dad
The string is Palindrome
 dad

Finds a given string is Palindrome or not
 Enter a string
 sister
The string is not Palindrome
retsis 

Download c program source code

• String reverse without using built-in method


• Palindrome