Installation for Windows:

As for today (2023-04-11) you will need the lastest version of:

1. flex-2.5.4a-1.exe

2. After that, do a full install in a directory of your preference without spaces in the name. I suggest C:\GnuWin32. Do not install it in the default C:\Program Files(x86)\GnuWin32 because it has problems with spaces in directory names, not to say parenthesis.

3. Also, consider installing Dev-CPP in the default directory C:\Dev-Cpp

4. After that, set the PATH variable to include the bin directories of gcc in C:\Dev-Cpp\bin and flex in C:\GnuWin32\bin. To do that, copy this: C:\Dev-Cpp\bin; C:\GnuWin32\bin and append it to the end of the PATH variable, defined in the place

Running your first program

Windows:

Open a prompt, cd to the directory where your ".l" is, and compile it with:

1. flex hello.l(file name)
2. gcc lex.yy.c
3. .\a.exe
4. Ctrl + Z (End)

Linux:

Open a prompt, cd to the directory where your ".l" is, and compile it with:

1. lex hello.l
2. gcc lex.yy.c -lfl
3. ./a.out
4. Ctrl + D (Stop taking inputs)