how to define

[gabghs]

the question was
Read one by one the characters of a sequence of characters ended by a point ". , And display the number of
'A' which contains.

I am not sure why this code isnt working
should i define the point in this case or what?

  int main() {
	//variable declaration
	char A,S,nb;
	//ask user
	while (S!='.')
	{
	cin>>S;
	if (S='A')
	{nb=nb+1;
    }
    }
    cout<<"nb of A is"<<nb;
	return 0;
}

[Repeater]

On line 8 you set the value of S to 'A'.

Perhaps you meant this:
if (S=='A')

What's the char A for on line 3? It doesn't get used. Remove it.

Is nb meant to be a number? If it is, you should make it a number type, like 'int'.

What value does nb begin with? What value did you want it to begin with? Better set it to that value at the start.

[Chervil]

Line 3. A is unused. S is not initialised, it contains garbage - what if it already contains '.'?
nb should be an integer, not a char. nb is not initialised, it contains garbage.
line 8 if (S='A' to test if the values are equal, use ==, not =.

[gabghs]

thx very much
it worked