Kernighans large earthquake problem: Difference between revisions

<p>PROBLEM: What if the file contains more information than expected? We would have to validate the lines that can be processed. For example, we might have a file with the following information:

</p>

<pre>

8/27/1883 Krakatoa 8.8

5/18/1980 MountStHelens 7.6

3/13/2009 CostaRica 5.1

Total events: 3

1/23/4567 EdgeCase1 6

1/24/4567 EdgeCase2 6.0

1/25/4567 EdgeCase3 6.1

1/25/4567 EdgeCase4 6.1

Total events: 4

Total Events in periods: 7

</pre>

<p>There are lines with 3 tokens, and the third token is numeric: it would be shown as a valid record!</p>

<p>On the other hand, HOPPER processes dates in DD/MM/YYYY format, and the file records dates in MM/DD/YYYY format: therefore, it is necessary to exchange "DD" for "MM", because HOPPER does not allow other types of format for "dates".</p>

<p>The final program would be as follows:</p>

<lang Amazing Hopper>

/* Kernighans large earthquake problem. */

#include <flow.h>

#include <flow-flow.h>

#define MAX_LINE 1000

#define SwapDayByMonth(_N_,_M_) TOK-SEP("/"), TOK(1), TOK-SWAP(2,Event), TOK-SEP(" ")

DEF-MAIN(argv,argc)

MSET(fd, Event )

TOK-INIT

OPEN-INPUT("datos.txt")(fd)

COND( IS-NOT-FILE-ERROR? )

TOK-SEP( " " )

TIC(t1)

WHILE( NOT( EOF(fd) ) )

LET( Event := USING(MAX_LINE) READ-LINE(fd) APPLY-TRM )

WHEN( LEN(Event) ){

WHEN( EQ?(TOK-COUNT( Event ),3) ){

Swap Day By Month(1,2)

WHEN( IS-DATE-VALID?( TOK(1) TOK-GET(Event) )){

TOK(3)

WHEN( GT?( VAL(TOK-GET(Event)), 6 ) ){

PRNL( Event )

}

}

}

}

WEND

TOC( t1, t2 ), PRNL( "Time = ", t2 )

CLOSE(fd)

ELS

PRNL("Error: ", ~GET-STR-FILE-ERROR )

CEND

END

</lang>