Program to check string is Palindrome or Not with better logic | Programmerdouts.

Practice Program

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Program to check string is Palindrome or Not.

A palindrome is a word, number, phrase, or other sequence of characters which reads the same backward as forward, such as madam or racecar or the number 10801.

Solution:

void main()
{
    int raise=1 ,i;

    char s1[20];


    printf("Enter the string: ");
    gets(s1);



 int l = strlen(s1);//storing length of string in variable l.


   for(i=0; i<(l/2); i++)
    {   //checking the character at index i with the character at index (l-1)-i are same or not.
        if(s1[i] != s1[(l-1)-i])//if characters are not same than will assign 0 to variable raise.
        {                   //assigning 0 to variable raise is indication that string is Not palindrome.
            raise = 0;
        }

    }
    if(raise == 0)
    {
        printf("String is Not palindrome");
    }
    else
        printf("String is  palindrome.");

}

Output1

Enter the string: programmerdouts

String is not palindrome

Output2

Enter the string: LeveL

String is palindrome

Output3

Enter the string: racecar

String is palindrome

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defining a function 'is_palindrome' which will check string is palindrome or Not

int is_palindrome(char s1[])
{
     int l = strlen(s1);//storing length of string in variable l.
 int i,raise = 0;


 char ch;
    for(i=0; i<(l/2); i++)
    {
        if(s1[i] != s1[(l-1)-i])
        {
            return 0;
        }

    }

}

Using above define function 'is_palindrome()':

void main()
{ int result;
    char s[20] = "code";

    result  =is_palindrome(s);

    if(result == 1)
    {
        printf("String is palindrome");
    }
    else
        printf("String is not palindrome.");

}

Output1

String is not palindrome

Using above define function 'is_palindrome()':

void main()
{ int result;
    char s[20] = "level";

    result  = is_palindrome(s);

    if(result == 1)
    {
        printf("String is palindrome");
    }
    else
        printf("String is not palindrome.");

}

Output2

String is  palindrome

Using above define function 'is_palindrome()':

void main()
{ int result;
    char s[20] = "programmer";

    result  = is_palindrome(s);

    if(result == 1)
    {
        printf("String is palindrome");
    }
    else
        printf("String is not palindrome.");

}

Output3

String is not palindrome

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