PTA 6-3 Judging Palindromic Strings

This problem requires writing a function to determine whether a given string of characters is a "palindromic". The so-called "palindrome" refers to the same string of forward reading and backward reading. Such as "XYZYX" and "xyzzyx" are palindrome.

Function interface definition:

bool palindrome( char *s );

The function palindromedetermines whether the input string char *sis a palindrome. If so, return true, otherwise return false.

Example of the referee test procedure:

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

#define MAXN 20
typedef enum {false, true} bool;

bool palindrome( char *s );

intmain ()
{
    char s[MAXN];

    scanf("%s", s);
    if ( palindrome(s)==true )
        printf("Yes\n");
    else
        printf("No\n");
    printf("%s\n", s);

    return 0;
}

/* Your code will be embedded here */

Input sample 1:

thisistrueurtsisiht

Sample output 1:

Yes
thisistrueurtsisiht

Input sample 2:

thisisnottrue

Sample output 2:

No
thisisnottrue

 

Author: C course group

Unit: Zhejiang University

Time limit: 400ms

Memory Limit: 64MB

Code length limit: 16KB

---

my code:

bool palindrome(char *s)
{
    bool equal = true;

    int i, j;
    int len = strlen(s) - 1;
    for (i = 0, j = len; j - i > 0; i++, j--)
    {
        if (s[i] - s[j])
        {
            equal = false;
            break;
        }
    }

    return equal;
}