Strange TurboC math error?

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I'm sorry if I've overlooked something obvious but I just can't figure out why this is giving me the wrong answer. I'm using TurboC 3.0 in DosBox on a FAT16 partition under XP SP2. Here's the code:

C#

void main(void)
{
   long lDays;

   lDays = 2011 * 365;
   printf("\nDays=[%u]\n", lDays);
}

According to my calculator (and running the same code in Borland C++ 5.5.1 under Windows) the answer is 734015 but the above code displays 13119!

This is a very small portion of a much larger project that I'm debugging in case you're wondering why.

Posted 12-Sep-11 6:38am

RDSchaefer

Updated 12-Sep-11 10:05am

Chris Maunder772.9K

v2

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3 solutions

Solution 4

C

#include <stdio.h>
#include <conio.h>
void main(void)
{
   long lDays;

   lDays = 2011L * 365;
   printf("\nDays: %ul\n", lDays);
   getch();
}

You need both the L(ong) specifier after (either of) 2011 or 365. You also need the %ul printf format specifier.

Gawd! Anybody got some airfreshener? The old decrepit, decayed beast that is TC3.0 is rotten and on the nose. I'd prefer TASM for a month of Sundays over TC!

Posted 12-Sep-11 8:31am

enhzflep

Solution 1

try the following :

C++

lDays = 2011L * 365;

Posted 12-Sep-11 6:42am

Mehdi Gholam

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Alan N · Accepted Answer · 2011-09-12T07:59:00

Solution 3

The lowest 16 bits of the value 734,015 represent the number 13,119 so you must have an incorrect format specifier. I'm no C expert but I think you need %ul (or %lu !) to display a unsigned long.

Alan.

Posted 12-Sep-11 7:59am

Alan N

Comments

RDSchaefer 12-Sep-11 18:36pm

Thanks! I tried %u, %U, and %ul but somehow forgot to check %lu. I'm getting old.