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Re: [vox-tech] C-Newbie needs help with a source-code

# Re: [vox-tech] C-Newbie needs help with a source-code

```At 06:06 AM 10/30/2003, you wrote:
```
what the program is about: you may input a decimal number and the program will convert it into a dual number... after this it will determine the length of the dual number (bestimme_laenge() ) then it should declare an array Dec[] with last position --> lange-1 then the positions Dec[i] ... i++ were filled in while while() after this it shut put out the positions of the array from Dec[lange] to Dec[0] so that the dual number is in the right order... but there are more numbers in the output the array shoul be long... o.O thats what i don't understand... i hope you can help me with this prob... greetz DaRkI sorry, my english is bad.. i know... but I hope you'll understand what i mean ;)

OK, but you're not giving us a whole lot to work with here. Let's break this into smaller problems.

So: you need to convert a decimal number into a binary number, then fill a variable-length array with the binary digits? And you don't know how big it's going to be?
Now, the problem here is that plain C will not allow you to declare new variables in the middle of a program (though C++ will). Your question seems to be: how do I know how big to make it? I can think of two different approaches:
1. Dynamic memory allocation. At the top of your program, declare a pointer (int *i) or an empty array (int i[]). Once you know how big the binary number is going to be, use malloc() to assign some memory to that pointer.
2. Use your brain. What's the biggest number a single integer variable can store? Why? How is this related to the largest size your array will ever be? Hint: look up sizeof(int) on your computer.

Hope this helps.

--nicole twn

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