Palindrom Palindrom - 7 months ago 88
Pascal Question

Division by 0 in TurboPascal7

I am working on my school project and I am (almost) furious about this issue. My solution's validity is 95 %, but I have 1 input wrong – I don't know the input, but I know, that the input failed because of the error code 200, which is divison by 0.

My project is this:


„The digit sum of an integer is defined to be the sum of the digits in the integer's written form. Usually we calculate the digit sum using a number's decimal (base 10) representation, but in this exercise we will compute it in a given base. Write a function that computes a natural number's digit sum when the number is written in a given base. Using this function, write a program that reads two natural numbers (each on its own line, and both in decimal representation): a base B and a number N. The output should be N's digit sum in base B (written in decimal representation).“


I have tried to fix the problem by adding 2 conditions, but it did nothing, mistake still exists.
I am using a formula, which can be found here https://en.wikipedia.org/wiki/Digit_sum .
Here is the code itself, it is not long.

program CifernySoucetZobecneny;

var
Soustava, Cislo, i: longint;
HorniMez: longint;
Soucet: real;

function Mocnina(Zaklad: longint; Exponent: longint): longint;
var
i, Pomoc: longint;
begin
Pomoc := 1;

for i := 1 to Exponent do
begin
Pomoc := Pomoc * Zaklad;
end;

Mocnina := Pomoc;
end;

begin
readLn(Soustava);
readLn(Cislo);

if (Soustava = 0) then
begin
writeLn('0');
exit;
end;

if (Soustava = 1) then
begin
writeLn(Cislo);
exit;
end;

HorniMez := Trunc(Ln(Cislo)/Ln(Soustava));
Soucet := 0;

for i := 0 to HorniMez do
begin
Soucet := Soucet + ((1/Mocnina(Soustava, (i)))*((Cislo mod Mocnina(Soustava, (i+1))) - (Cislo mod Mocnina(Soustava, i))));
end;

writeLn(Soucet:0:0);
end.


I would be grateful if someone could look at the code and told me, where am I dividing by 0, because I tried many inputs, spend many hours on this and did not come with the correct solution. Thank you all.

PS: I am Czech, so the names of the variables and functions are not in English, sorry for that, but I hope, that it will not be a problem.

Answer Source

When Cislo = 0, a following calculation of Ln(Cislo) gives the runtime error 200. That is because Ln(0) is undefined (outside the allowed range of Ln()).

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