I apologise if it is a basic or silly question. What is the difference between char* and LPSTR. where the sizeof both gives 4 bytes in my compiler. Can someone explain me in detail. thanks..
LPSTR is a Windows type, meant to be the same regardless of what platform you were compiling on. It's a long pointer to a string.
Back in the days of segmented architecture (the old 64K segments, not the newer selector-based segmented memory), where you had tiny, small, medium, large and huge memory models, it was important that the Windows type was always the same, regardless of what type of pointer char * was.
So, if you complied with different compilers where the underlying types were different, the windows.h header file would define LPSTR to compensate for that.
For example, Borland C may have had a sixteen-bit char * and LPSTR may have had to be defined as far char * for it. In a compiler where char * was already a long/far pointer, LPSTR would have just used that instead.
Nowadays, with 32+ bit flat models, there is probably no real need for such shenanigans, though it may still happen with things like thunking between 64-bit and 32-bit code. Still, the types defined back then are still with us and still very much in use.