C program to check for palindromes

Palindrome Number : If number is like 121 and reverse of that number is also same. So we can say that the number is palindrome. Palindrome String : If string is like 'radar' and reverse of that string is also same then that string is known as palindrome string.

1) C program to check palindrome number

 #include <stdio.h>  
 int main()  
 {  
   int no, reverse = 0, temp;  
   printf("Enter No : ");  
   scanf("%d", &no);  
   temp = no;  
   while( temp != 0 )  
   {  
     reverse = reverse * 10;  
     reverse = reverse + temp % 10;  
     temp = temp / 10;  
   }  
   if ( reverse == no )  
     printf("Palindrome Number");  
   else  
     printf("Not a Palindrome Number");  
   return 0;  
 }  

2) C program to check palindrome string using string library function

 #include<stdio.h>  
 #include<string.h>  
 int main()  
 {  
   char str[100], temp[100];  
   printf("Enter String : ");  
   gets(str);  
   strcpy(temp,str);  
   strrev(temp);  
   if( strcmp(str,temp) == 0 )  
     printf("String is palindrome");  
   else  
     printf("String is not palindrome");  
   return 0;  
 }  

  3) C program to check palindrome string without using string library function

 #include<stdio.h>  
 int main()  
 {  
   char str[100];  
   int begin, middle, end, length = 0;  
   printf("Enter String : ");  
   gets(str);  
   while( str[length] != '\0' )  
     length++;  
   end = length - 1;  
   middle = length / 2;  
   for( begin = 0 ; begin < middle ; begin++ )  
   {  
     if ( str[begin] != str[end] )  
     {  
       printf("String is not palindrome");  
       break;  
     }  
     end--;  
   }  
   if( begin == middle )  
     printf("String is palindrome");  
   return 0;  
 }