exponential growth problem with showing 19 digits

[martingz]

It could be that it only shows 19 and rounds the last

[Claudio Ricardo]

Hi... I thing but not sure, Harbour use IEEE 754 Math standard inherited from Clipper.
https://en.wikipedia.org/wiki/IEEE_754

The solution would be to divide into two words, multiply the least significant (right) first, add the carry digit to the second (left),
multiply it and then concatenate the results in a string. cResult := "left_result" + "right_result"

[SALINETAS24]

Hi friends,
surely most of you if not all know the story of the grains of rice on a chessboard. On the first field you put one grain, on the second field the first field is doubled, on the third field the second field is doubled and so on up to field 64. I have written a small program to demonstrate every step in this calculation. It works fine, but on the 64th field the result is unexpected: the 6 most right digits should be "775808" but it turns out they are :"776000".
I don't know why that happens. 19 digits should be possible, the number on field 63 also has 19 digits, which are shown exactly.

I have attached a zip file with all files necessary and a screenshot. I use the 32 bit version of hmg as you can see on the screenshot. Would a 64 bit version show the complete right 19 digits? Who can explain?

Thx Robert

Hola Robert.., Harbour es un fiel heredero de la arquitectura del CLIPPER 5.x y algunas de las carateristicas que presentaba el Clipper en su día eran las siguientes .....

Code: Select all

1 - Nº. máximo de registros por base de datos, 1000.000.000
2 - Nº. máximo de caracteres por registro, RAM disponible
3 - Nº. máximo de campos por registro, RAM disponible
4 - Nº. máximo de caracteres por campo, 32 kb
5 - Nº. de dígitos de precisión en operaciones de cálculo, 18
6 - Nº. máximo de caracteres en una clave de indexación, 250
7 - Nº. máximo de variables de memoria, 2048
8 - Tamaño máximo de una variable de memoria, 64 kb
9 - Nº. máximo de dígitos en una variable numérica, 19
10 - Nº. máximo de tablas, 2048

El punto 5 y el punto 19 te indican las limitaciones del lenguaje.
Ademas debes tener en cuenta que el signo (+ o -) también cuenta y está presente en la longitud.

https://elguille.info/clipper/manual.htm

Salud para todos y vamos con una cervecita bien fresquita !!!

[ROBROS]

Hi,
50 years ago I was taught Latin at school, so I know, that cervecita bien fresquita means fresh beer. Born and brought up in Bavaria I bid you and all forum members a "Prost" what origins from the Latin Prosit.
Thank you for explaining the limitations of clipper. My demonstration of exponential growth is an exception, I'm sure I never again will handle such big numbers.

Robert

[SALINETAS24]

Buenos días, aquí tienes la solución para realizar el calculo. Ahora podemos jugar a contar los granos de trigo hasta mas allá del cuadro 64. Hasta el infinito y más allaaaaa!! Lo siento.

Vamos con una ronda virtual de cerveza fresquita.., que esta la pago yo.!!

[Claudio Ricardo]

Exacto... Así hacía cuando programaba microcontroladores de 8 bits en assembler
para manejar cifras mayores a 255 (por eso puse arriba lo de dividir en 2 words)
Gracias por la cervecita virtual ! no imaginás el calor que hace acá.

Exactly ... This is how I did when programming 8-bit microcontrollers in assembler
to handle figures greater than 255 (that's why I put the divide into 2 words above)
Thanks for the virtual beer ! You cannot imagine how hot it is here.

[ROBROS]

Claudio wrote: cifras mayores a 255

"cifras": in German we use the word "Ziffer"

Bottoms up and cheers!