![]() Strcpy(dst, src) The function call operator in action (notice the function pointer on the left side). int *array would be illegal here the compiler would not accept us assigning the Remember the NUL terminator!Ĭhar src = "This is a string.", dst Note that we use the notation because we are declaring an array. Here’s a declaration of a three- int array: This is not useful for anything, except to declare function pointers (described later). ![]() Incidentally, C allows zero or more levels of parentheses around the variable name and asterisk: Just use your own judgment.įinally, I should point out that you can do this just fine: The absolute clearest is to keep every declaration on its own line, but that can take up a lot of vertical space. It’s even clearer to put the non-pointer variables first: It’s possible to do the single-line declaration in a clear way. Think of it as assigning each variable a base type ( int), plus a level of indirection, indicated by the number of asterisks ( ptr_b’s is zero ptr_a’s is one). If you split the declaration of ptr_a and ptr_b into multiple statements, you get this: It is not a pointer.Ĭ’s declaration syntax ignores the pointer asterisks when carrying a type over to multiple declarations. Given this, what is the type of ptr_b? int *, right? then you can declare multiple int-pointer variables by simply giving the int-pointer type ( int *) followed by a comma-separated list of names to use for the variables ( ptr_a, ptr_b).and a single statement can declare multiple variables of the same type by simply providing a comma-separated list ( ptr_a, ptr_b),.If the type of a variable containing a pointer to int is int *,.The obvious way to declare two pointer variables in a single statement is: The use of pointers to pointers is called multiple indirection. An int **’s type is int * (it points to a pointer to int). Thus it is an ‘ int pointer’ (a pointer to int). You could put a different pointer in the foo_ptr box, and the box would still be foo_ptr. The point of that is that the pointer is not the variable! The pointer to foo is the contents of foo_ptr. (Thus, ‘pointer variable’ really means ‘variable of a pointer type’.) There are, however, variables with different types. In fact, grammatically speaking, there is no such thing as a ‘pointer variable’: all variables are the same. ![]() This is true of all variables, regardless of type. When you access the address, you actually access the contents of the box it points to. foo is a box that is sizeof(int) bytes in size. &foo is the address of foo (which is why & is called the ‘address-of operator’). Its location in memory is called its address. We have initialised it to point to foo.Īs I said, foo occupies some memory. On a PowerPC, it occupies four bytes of memory (because an int is four bytes wide).įoo_ptr is declared as a pointer to int. ![]()
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