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3 votes
Accepted

Pset4 recover, comparing hex in if statements

@Blauelf is correct: you can't count on char to be an unsigned 8-bit int. However, you can use a typedef to make certain that a BYTE is really a byte. Look at these type definitions, borrowed from ...
hotwebmatter's user avatar
  • 3,050
2 votes

Pset4 recover, comparing hex in if statements

char can be signed or unsigned by default (and is 8-bit on every system I know, but that's not guaranteed by the specs). On this system, char datatype is signed 8-bit int, ranging from -128 to 127, ...
Blauelf's user avatar
  • 21k
2 votes
Accepted

What is the return value when isalpha() evaluates to true?

The problem is a lack of understanding of how many of these functions work. While you would think that isalpha() would return a bool, it doesn't. Instead, it returns a number. If it is false, it ...
Cliff B's user avatar
  • 69k
1 vote

Pset4 recover.c compiles, but can't seem to print Jpgs at all

I tried to isolate some of the codes in modular form and created a file just to check this code. It seem to be the problem. Did I declare the function within the if statement wrongly? #include <...
olafironfoot's user avatar
1 vote
Accepted

Pset4 recover.c compiles, but can't seem to print Jpgs at all

Just to be crystal clear: if (data[3] != 0xe0 || data[3] != 0xe0 || data[3] != 0xe1 || data[3] != 0xe2 || data[3] != 0xe3 || data[3] != 0xe4 || data[3] != 0xe5 || data[3] != 0xe6 || data[3] != 0xe7 ||...
hotwebmatter's user avatar
  • 3,050
1 vote
Accepted

Are boolean variables left uninitialized true or false?

There is no default value initialization guarantee of any kind in C. I don't know where you learned the default value of booleans is false but I strongly question that information and disagree with it....
UpAndAdam's user avatar
  • 1,401
1 vote
Accepted

Do computers have to check if (false) the same way as whether (0 != 0), etc.?

Interesting question. The computer has to evaluate whatever is in the parentheses. The more complicated, the more it has to process. If there is only a variable inside the parentheses, then the ...
Cliff B's user avatar
  • 69k
1 vote
Accepted

Week 2 Lecture - Functions - Valid Triangle

Just like the function printf, the valid_triangle function has to be called from within main in order to execute and produce results.
DinoCoderSaurus's user avatar
1 vote

Else If Boolean Statements of Equality In the Case of Complex Numbers

That example doesn't say what data type x and y are, but generally you can assume that numerical variables are real numbers in programming, unless specified otherwise. There is a way to work with ...
Llenk's user avatar
  • 744
1 vote
Accepted

What's in the bool function parenthesis?

No such thing as a silly question. It just means that you haven't learned it yet. That's all. ;-) This is a function "signature". It defines what is expected to be passed to the function. int rank ...
Cliff B's user avatar
  • 69k
1 vote
Accepted

Pset3 is_rest does not compile right?

You get this error because it is possible to get to the end of the function without giving a value to return. Specifically, there's only the one return statement in the code. If value is not 0, then ...
Cliff B's user avatar
  • 69k
1 vote

pset2 caeser boolean returns

if (isdigit('k')) 'k' refers to the character or letter k, note that atoi converts the character of the command line to an integer, surely you want to do if (isdigit(argv[1]) however this is not ...
MARS's user avatar
  • 5,169
1 vote
Accepted

A question about boolean expressions

Yes there is, a couple ways actually. These all work the same way: if ( !boolean ) do... if ( boolean == false ) do... if ( boolean ) not here.. else do... I hope this helps.
dLopez's user avatar
  • 122

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