CONVERT A REAL VALUE TO AN INTEGER

[PROFESSORSPARKIE]

HOW DO I CONVERT A REAL VALUE TO AN INTEGER?

VAR
LOC : LONGINT;
WORK1 : REAL

LOC := INT(WORK1);

GIVES AN ERROR 75 DATA MISMATCH

I KNOW IT MUST BE SIMPLE BUT I O NOT HAVE A GOOD MANUAL & I HAVE TRIED MANY THINGS. ANY HELP WILL BE APPRECIATED.

THANKS IN ADVANCE, I DO SIMPLE THINGS LIKE THIS IN MANY OTHER LANGUAGES BUT NOT IN PASCAL.

 

[stackdump]

You can either use TRUNC() which will strip off anything after the decimal point (so it always rounds down) or you can use ROUND() which rounds to the nearest integer.

 

[PROFESSORSPARKIE]

Sorry, I should have made my self clear. I am going to use the value to seek in a direct binary file which requires a longint or integer in the SEEK procedure. It will not accept a real value.

I am developing the location by doing a square of the key, dividing by the number of allocated slots and going directly to the record. I also use a spill forward with space wrap around for synonyms.

I teach and am using a qbasic program to load the file, pascal to update it and cobol to list it with a perl program supporting a cgi inquiry. The class is a program language surver course. This is the only part I am having trouble with.

 

[Glenn9999]

Perhaps you should clarify your requirements. Stackdump provided the proper answer, by all indications.

 

[PROFESSORSPARKIE]

I am going to use SEEK and BLOCKREAD PROCEDURES TO BE ABLE TO RANDOM READ FROM A FIXED LENGTH RECORD FILE. THE SEEK REQUIRES INTEGER VALUE FOR THE RECORD LOCATION based on a randomized location

LOC : LONGINT;
BUFFER : ARRAY [1..43] OF CHAR;{MAX_BUF] OF CHAR;}
BYTES_READ : WORD;
REALWORK1 : REAL;
SLOTS : REAL;


LOC := (INT(REALWORK1 / SLOTS) * SLOTS ) + 1.0;
SEEK(EMP_FILE, LOC);
BYTES_READ := 0;
BLOCKREAD(EMP_FILE, buffer, 1, BYTES_READ);

LOC must be integer type but my calculations are in real numeric values. This type of processing is often used in high performance requirements where record retrieval need to approach 1 SEEK 1 READ per record. Using 1 or more index reads can raise the cost of read performance greatly.

Other languages handle this more easily.

 

[PROFESSORSPARKIE]

The question is easy. How do I take a REAL variable value and put the integer part in an INTEGER variable.

 

[Glenn9999]

VAR
LOC : LONGINT;
WORK1 : REAL

LOC := trunc(WORK1);

 

[PROFESSORSPARKIE]

glenn, THAT WORKED!!!!
Thanks

I wonder why
LOC := INT(WORK1);

Since the value on INT is an integer. So goes the nature of programming languages. I should have tried the answer that stackdump gave me. I was so sure that INT & TRUNC worked the same.

I am sorry stackdump. THANKS to ALL.

 

[Glenn9999]

Int() returns an extended/real value.

loc := Int(3.14157);

loc has to be extended/real, and the answer will be 3.000000000.

 

[lionelhill]

Really, before truncating it, you should be asking yourself why this variable was ever real in the first place. You can never have a location of 3.14 in a file.

 

[PROFESSORSPARKIE]

To glenn9999,

None of the references I had available said that INT returned a long integer. In other languages I have used an INT function took a real/float and returned an integer value and I let myself go down that path.

lionelhill,

A routine I had just converted from another language that did not have a remainder function took the key and divided by the number of slots to get a relative file location in a file space. I have done this type of high performance processing for over 40 years. You get a real value and just round off to an integer.

As I said early on I have manuals that are short on internals details. Any recommendations for a great text? There arn't many options now like with perl, java, etc.

Again THANKS to all. It had been many years since I wrote programs in Pascal except for "Hello World" or simple report listings. It has been interesting. Direct(binary) file processing requires a detailed understanding of disk file management.

ProfessorSparkie