What happens when a char array is initialized to '\0'?

Question

I have a char array of size 512 ie

char buffer [512];

This variable after some point is modified to this

buffer [40] = '\0';

What does this assignment does to the variable? Does it initialize the first 40 char in the array to null?

Answer 1

No. It stores the value NUL at the 41st position in the array.

To init the first 40 characters to NUL

memset(buffer, '\0', 40);

To init the entire buffer to NUL at compile time, try

char buffer[512] = {0}; 

or

char buffer[512] = "";

To init it at run time, try

memset(buffer, '\0', sizeof (buffer));

Answer 2

It assigns only the 41st char in the array to \\0 . Thus now the string consists of what the chars represent in the first 40 elements of the array ie 0 to 39th indices (assuming there were no other NUL characters in any of the previous elements -Thanks Kerrek SB!!) .
Hope this helps!

Answer 3

它将字符'\\0' （即NUL字符）分配给第41个数组元素。