In C++, I have a char array defined as:
char miniAlphabet[] = {'A','B','C','D','E', '\0'};
I want to modify the values of this array from other functions without passing it to those functions. This is where you use pointers right?
So my question is what is the correct way to make a pointer to this char array. Would I just make a pointer to the first element and then when I want to modify the values I step through memory until I hit the end character?
char miniAlphabet[] = {'A','B','C','D','E', '\0'};
These are equivalent.
char *p1 = miniAlphabet;
char *p2 = &(miniAlphabet[0]);
Note that the () are useless for the operators' precedence, so
char *p3 = &miniAlphabet[0];
In C/C++ the name of an array is a pointer to the first element of the array.
You can then use pointers' math to do some magic...
This will point to the second element:
char *p4 = &miniAlphabet[0] + 1;
like
char *p5 = &miniAlphabet[1];
or
char *p6 = miniAlphabet + 1;
*p1 you are dereferencing the pointer (accessing the value pointed by the pointer), so you are obtaining the first element. char p2 = *p1;. A pointer to a pointer would be char **p3 = &p1;char* is both a pointer to a single char AND a pointer to what is called a C string (a zero terminated string). It depends on how you use it.The position of the array in memory is the same as the position of its first element. So for example, both function signatures below are equivalent:
function changeArray(char[] myArray);
function changeArray(char* myArray);
And you can call either version like this:
changeArray(miniAlphabet);
...or
changeArray(&(miniAlphabet[0]));
If you pass an array to a function, you ARE passing by reference as an array variable is really just a pointer to the address of the first element in the array. So you can call a function like this:
funcName(miniAlphabet);
and receive the array "by reference" like this:
void funcName(char *miniAlphabet) {
...
}
In short, yes. When you create the array miniAlphabet is a pointer to the array of the size and type you defined. Which is also the pointer to the first element.
An example of what you are suggesting.
void foo(char *array)
{
array[0] = 'z';
array[2] = 'z';
}
...
char myArray[] = { 'a', 'b', 'c'};
foo(myArray);
//myArray now equals {'z', 'b', 'z'}
also of note, dereferencing myArray gives you the value in the first element.
