程序代码：

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


int
palindrome( char *string );

int
main( void )
{
    char s1[10000];
    int i;
    int ch;
    FILE *fp;

    if( NULL == ( fp = fopen( "word.txt","r" ) ) )
    {
        fprintf( stderr, "Error\n" );
        exit( EXIT_FAILURE );
    }

    for( i = 0; 10000 - 1 > i && EOF != ( ch = fgetc( fp ) ); i++ )
        s1[ i ] = ch;
    s1[ i ] = '\0';

    while( 'y' == ( ch = getchar() ) )
    {
        while( '\n' != getchar() )
            ;
        if( 1 == ( i = palindrome( s1 ) ) )
            printf( "Yes\n" );
        else if( -1 == i )
            printf( "Error\n" );
        else
            printf( "No\n" );
    }

    fclose( fp );

    getchar();

    return 0;
}


void
reverse( char *src );
enum { Error = -1, No = 0, Yes = 1};


int
palindrome( char *string )
{
    char *s1, *s2;
    char temp[ strlen( string ) ];//VS或VC这一行可能通不过编译。
    int CharAmount;
    int Limit;
    int i;


    if( 0 ==  strlen( string ) )
        return Error;


    for( CharAmount = 0, i = 0; '\0' != *string; string++ )
        if( isalpha( *string ) )
        {
            temp[ i++ ] = tolower( *string );
            CharAmount++;
        }
    temp[ i ] ='\0';


    Limit = CharAmount / 2;
    s1 = ( char * )malloc( ( Limit + 1 ) * sizeof( char ) );
    s2 = ( char * )malloc( ( Limit + 1 ) * sizeof( char ) );
    if( NULL == s1 || NULL == s2 )
        return Error;


    strncpy( s1, temp, Limit );
    *( s1 + Limit ) = '\0';

    if( CharAmount % 2)
        strncpy( s2, temp + Limit + 1, Limit );
    else
        strncpy( s2, temp + Limit, Limit );
    *( s2 + Limit ) = '\0';
    reverse( s2 );

    i = strcmp( s1, s2 );
    free( s1 );
    free( s2 );

    if( 0 == i )
        return Yes;
    else
        return No;
}


void
reverse( char *src )
{
    char *s1, *s2;
    char temp;

    s1 = src;
    s2 = src;

    while( '\0' != *s2 )
        s2++;
    s2--;

    for( ; s1 < s2; s1++, s2-- )
    {
        temp = *s1;
        *s1 = *s2;
        *s2 = temp;
    }
}

[此贴子已经被作者于2017-3-13 15:41编辑过]

[此贴子已经被作者于2017-3-13 16:46编辑过]

[此贴子已经被作者于2017-3-13 17:04编辑过]