C程序需要的解释

Question

In a c-book I bought, an exercise program is given as

what is the output for the following code snippet?

printf(3+"Welcome"+2);

the answer I got is me (by executing it in TC++)

But I can't get the actual mechanism. please explain me the actual mechanism behind it.

Answer 1

It's called pointer arithmetic: 2+3=5, and "me" is the rest of the string starting at offset 5.

PS: throw away that book.

Answer 2

When this is compiled the "Welcome" string becomes a const char * , pointing to the first character of the string. In C, with character strings (like any pointer), you can do pointer arithmetic. This means pointer + 5 points to 5 places beyond pointer.

Therefore ("Welcome" + 5) will point 5 characters past the "W", to the substring "me."

On a side note, as other have suggested, this doesn't sound like a good book.

Answer 3

A string (like "Welcome" ) is an array of characters terminated by the NUL-character (so it's actually "Welcome\\0" ).

What you are doing, is accessing the fifth character of it (3 + 2 = 5). This character is 'm' (array indices start at 0).

printf will continue to read till it hits the NUL-character.