What is the difference between char zero and normal zero?

Hi, I am not up to date with latest c++ and how it is strongly typed nowadays:

Concept

The concept is that the memory representation changes depending on the declaring type.

Char is usually defined as an 8 bit memory cell, int is usually defined as 32bit or 64bit

char x = <whatever>; //you are reserving 1 byte
int x = <whatever>; //you are reserving (let's say) 4 bytes

The literal '0', in C and C++ represent the character '0' and not the value 0, for example the ascii code for character '0' is 48 (decimal), the Nul character is represented by the literal '\0' or '\x0' instead.

How it works

TO understand how it works, imagine how your variable lives in the computer: it is a portion of the RAM memory, suppose that memory bound to your variable is located at address 100.

Here is your ram before you initialize your variable, its content is undefined:

100: ?
101: ?
102: ?
103: ?

this is how the various different versions you posted affect the status of your memory:

char x=0; I do not like that so much, but for the compiler is all good.

100: 0
101:  (not allocated to x, cause is char that only use 1 cell)
102:  (not allocated to x)
103:  (not allocated to x)

int x=0; (that is good, no conversion required)

100: 0
101: 0
102: 0
103: 0

char x='0'; (that is good, no conversion required)

100: 48d (48 is decimal ascii code for characted '0')

char x = '\0'; (same as above but '\0' is a char literal representing ASCII NUL, this is the way I prefer to initialize a char to 0)

100: 0

int x = '0'; I do not like that 'cause right part is a literal, i can tolerate the assignment of a char variable to an int.

100: 48d (in this example the machine is little endian, LSB stored at lower address)
101: 0 
102: 0
103: 0