Decoding program help

Dear fellow members,

Im a first year physics student and learning my first programming language and this is C++.
We have an assignment where we are supposed to make a program that can compress text files in the following way:

aaaaabbbbbbbbb/////////


5555555555

(becomes)->

a5b9/9


/510

and the decoding part must do the opposite.

I already got the coding part down:

Code:

 

void coderen (ifstream & input, ofstream & output) {
	int counter;
	counter = 1;
	char karo, karn;
	karo = input.get(); //first character is fetched
	while (! input.eof()){	

		karn = input.get(); //new character is fetched

		if ((karo == karn) && !(karo == '\n')) {
			counter ++;
			}	

		else {
			output.put(karo);
		
			if (counter > 1) {
				output << counter;
				} //if

			if ((karn >= '0') && (karn <='9')){		
				output << '\\';
				}//if kar = a number, put a slash.
					
			counter = 1; 
			} //else	
	
		karo = karn; //old character becomes new character

 		} //while not end of file
	
}//code

But now I`m trying to write the code for the decoding and I`m having some difficulties.
My idea was that I take the first character of the file i need to decode, now I take the following character and if this is a number I`ll put that information in a counter and look at the following character and if that is a number I`ll add that info to the counter untill I encounter a non-number, then I`ll use a loop to write the first non-number the number of times is given by the number after this character in the "to decode" file.
But the bad part is, it doesnt work the way I intended: a5 doesnt give me aaaaa but instead gives me a/5.

So I`m looking for advice on this piece of code, I appreciate every help I can get. Here is the decoding code

Code:

void decoderen (ifstream & input, ofstream & output) {

	int counter, tempcounter;
	counter = 0;
	tempcounter = 0;
	char karo, karn;             //old character, new character
	karo = input.get();
	
	while (! input.eof()){
	
		karn = input.get();
	
		while ((karn >= '0') && (karn <= '9')){		
		
			if (karn = '0'){
				tempcounter = 0;}
			else if (karn = '1'){
				tempcounter = 1;}
			else if (karn = '2'){
				tempcounter = 2;}
			else if (karn = '3'){
				tempcounter = 3;}
			else if (karn = '4'){
				tempcounter = 4;}
			else if (karn = '5'){
				tempcounter = 5;}			
			else if (karn = '6'){
				tempcounter = 6;}
			else if (karn = '7'){
				tempcounter = 7;}
			else if (karn = '8'){
				tempcounter = 8;}
			else {
				tempcounter = 9;}
	
			counter = counter*10 + tempcounter;
			karn = input.get();
			} //while
		
		cout << tempcounter << endl;
		cout << "counter after countingloop" << counter <<endl;
		

		while (counter > 0){
			output.put(karo);
			counter = (counter-1);
			} //while

		cout << counter <<endl;
	
	}// while

} //decode

Code:

if (karn = '0')

Those are all assignments, not comparisons.

I hate the way that they always seem to give your first compression assignments using a text-based and ambiguous representation.
E.g, what is 1234 supposed to decompress to:
113333, or
11111111111111111111111 and then four of whatever comes next, or
two hundred and thirty four ones?


When you find yourself repeating lines of code with no difference other than a number is incremented by one, then you're doing it wrong. Use simple calculations or look-up tables instead of code duplication.

I`m obviously still such a beginner because of the karn = '0' instead of ==. Thanks for the help because now I can get get on with my assignment, saves me a lot of trouble. This board is very helpfull for me and you guys are doing us beginners a great favour but I`m not sure if it is ok to ask these beginner questions here. Is there maybe a board for super duper beginners like me?

When you find yourself repeating lines of code with no difference other than a number is incremented by one, then you're doing it wrong. Use simple calculations or look-up tables instead of code duplication.

What do you mean exactly by this? I know you are talking about my way to convert a character to a integer but I though this was a pretty simple way to do it. Could you give me some clues about a better way to do it as you implie?

I hate the way that they always seem to give your first compression assignments using a text-based and ambiguous representation.
E.g, what is 1234 supposed to decompress to:
113333, or
11111111111111111111111 and then four of whatever comes next, or
two hundred and thirty four ones?

Maybe I was not clear about this but a number like 1234 preceded by a character becomes 1234 times that character and a / followed by 1234 becomes 234 times a 1. You will never get something like 12121212 -> 12 x 6 because of the nature of the encoding as this is a very basic compressing algorithm.