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Hi, I wanted to make a small game (For learning the techniques) and I wanted to create a main info file, containing the tilemaps, image names etc. but how can I jump to a marked place in the file and read it until the next mark is reached? I know it can be solved in many ways, but which one would you suggest me?
That's a good idea (very usual) but how can I search for a specific string in a file for using it? Or make an index, such as LEVEL1 -> 8 (in lines)?
Neither of these works on a line basis, only on a byte basis. If you want to store a byte index, I suppose you could. If you know which line you're looking for, you have to read a line, throw it away, read a line, throw it away, ..., read a line, throw it away, and then read the line you want.
Well, ok, i'll try. But how can I scan for a line containing LEVEL x.y? I mean, scanf would try to get the values and save them in x and y, not compare them.
scanf isn't supposed to compare them. You're supposed to compare them. Read something in; if it's what you want, then yay; otherwise, do it again.
you mean like:
Code:while(getline(line, SYMBOL_LENGTH, file) != NULL) {
if (line == {'@', 'L', 'V', 'L'}) {
fscanf...
}
}
The idea looks reasonably correct, but the execution is all wrong. You can't compare strings with ==, and the rest of the line is in line too, not just the first bit, so you'll have to not read from the file, but read from line.
Sorry, i did it wrong the first time. Anyway now it crashes. How can I get the first lets say 5 chars from a string? with memcpy? And should I use strcmp instead of ==?
PS: Why the hell does gdb report a sigsegv fault in ntdll!RtlInitializeHandleTable()
Since == is amazingly wrong and strcmp is amazingly right, I would go with strcmp. If you only want to compare the beginning of your string, you could use strncmp instead.
Sorry, now it goes. The problem was the file. Thanks for your help!
Do you ever get into the if statement? What does your line variable hold, other than what you expect?
Probably because fscanf() doesn't return 4 and doesn't pass over the stuff you wanted it to, so it gets stuck - which is a common scanf() scenario when the input and the expected input aren't a good match (e.g. text when numeric input is expected).
By the way, if the file isn't enormous (as in, many megabytes) then it may actually work better to just read all of the file into memory at once into some suitable data structure, and then search inside the data structure as needed, rather than searching the file content.
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Mats