/* --------------------------------------------------------------------- 
**  Figure 16.1: Sequential search of a table.
**  Figure 15.16 was adapted to create the read_file() function..
** --------------------------------------------------------------------- 
*/
#include "tools.h" 

#define LENGTH 20   

int  read_file( int data[], int nmax, stream fin ); 
int  sequential_search ( int data[], int n, int key );    

void main( void ) 
{  
    int n;                       /* # of data items; will be <=LENGTH. */ 
    int items[ LENGTH ];         /* An array for the data to be searched. */  
    int key;                     /* Value to search for. */
    int where;                   /* Index where key was found. */

    stream fin = fopen( "search.in", "r" );    
    banner();
    if (fin==NULL) fatal( " Fatal error: cannot open search.in." ); 
    printf( " Reading data from search.in.\n");  
    n = read_file( items, LENGTH, fin );

    printf( " %i items were read; beginning to search.\n", n );   

    for (;;) {
        printf( " Enter search key (negative to end): " );
        scanf( "%i", &key );
        if (key<0) break; 
        where = sequential_search( items, n, key );
        if (where>=0) printf( " Item: %i \t found in slot %i\n", key, where ); 
        else puts( " Item not found." );
    }
    bye();  
}           

/* ------------------------------------------------------------------------ */
int read_file( int data[], int nmax, stream fin )
{      
    int k;                          /* subscript variable for loop */              
    int flag;                       /* for fscanf() return value */

    for (k=0; k<nmax; ) {           /* Don't read beyond end of data array. */
        flag = fscanf( fin, "%i", &data[k] );
        printf( " %i\n", data[k] ); /* Echo it to screen. */    
        if (flag == 1) ++k;         /* all is well -- count the item. */ 
        else if( feof(fin) ) break; /* no more data is available. */
        else {                      /* bad data -- note, skip, & continue. */
            fprintf( stderr, " ---  Bad data while reading slot %i: ", k );
            cleanline( fin );
        }
    }
    fclose( fin ); 
    return k;  
}

/* ------------------------------------------------------------------------ */
int sequential_search( int data[], int n, int key )   
{
    int scan;                       /* Loop counter and array index. */

    for (scan = 0; scan < n; ++scan) {
        if (data[scan] == key) return scan;
    }
    return -1;  
}