C语言K&R习题系列——使用缓冲区函数接受长字符输入

原题：

Write a program to print all input lines that are longer than 80 characters. 

实现起来不算难，关键是用到了缓冲区，很不错的一种思想！

/* Write a program to print all input lines
 * that are longer than 80 characters
 */
  
 #include < stdio.h >
  
 #define MINLENGTH 81
  
 /*readbuff: read all input characters*/
 int readbuff ( char *buffer )
 {
    size_t i = 0;
    int c;
     
    while( i < MINLENGTH )
    {
        c = getchar();
         
        if ( c == EOF )
        {
            return -1;
        }
        if ( c == '\n' )
        {
            return 0;
        }
         
        buffer[i++] = c;
    }
     
    return 1;
 }
  
 /*copyread: copy the inputs that longer than 80 characters*/
 int copyread ( char *buffer )
 {
    size_t i;
    int c;
    int status;
     
    status = 1;
     
    for ( i = 0; i < MINLENGTH; i++ )
    {
        putchar ( buffer[i++] );
    }
    while ( status == 1 )
    {
        c = getchar();
        if ( c == EOF )
        {
            status = -1;
        }
        else if ( c == '\n' )
        {
            status = 0;
        }
        else
        {
            putchar(c);
        }
        putchar ( '\n' );
    }
    return status;
 }
  
 /*print the inputs that longer than 80 characters*/
 main ( void )
 {
    int status;
    char buffer[MINLENGTH];
     
    /*initialize*/
    status = 1;
    while ( status != -1 )
    {
        status = readbuff ( buffer );
        if ( status == 1 )
        {
            status = copyread ( buffer );
        }
         
    }
     
    return 0;
 }