Thread: how to open exe files

Get a disassembler.

A disassembler will give you assembly-language code, NOT C++ code. You might be able to understand the assembly code for "Hello World", but the assembly code for a real-world program is going to be tough to understand. (There won't be any comments.)

Last time I did a quick Internet search, I found a decompiler, but it was very expensive... over $1000, I think.

Compilation is basically an irreversable process. Different compilers will give you different exe files, and you can write different C++ code that will give you the same exe file. For example, if you change a variable name, the exe code will not change. There's more than one way to make a loop. The decompiler won't know what type of loop was in the source code. The decompiler won't know if there were several cpp files, or one big cpp file...

The machine code (exe file) doesn't need comments, variable names, or function names. Thse are lost during linking/compilation. A decompiler will generate its own variable & function names... meaningless names like Variable1 and Function1().

There is LOTS of information lost diring compilation! A decompiler can generate C++ source code, but it cannot regenerate the original source code!

Assembly language is reversable, (except for variable names, etc.) because there is a one-to-one relationship between assembly language and machine language. That is, every line of assembly language code corresonds precisely to a single line of machine language code.

An exe file is machine language... just a series of binary numbers which represent processor-instructions, values, and addresses.

The bottom line is: Sometimes disassembly is useful. Decompilation is rarely useful. It's usually easier to re-write the code!

Check out W32DAsm.

Kuphryn