Menu
What happens when I declare say multiple variables on a single line? e.g.
int x, y, z; All are ints. The question is what are y and z in the following statement?
int* x, y, z; Are they all int pointers?
836
If your variables are the same type, you can define multiple variables in one declaration statement. For example: int age, reach; In this example, two variables called age and reach would be defined as integers.
Declaring multiple variables in a single declaration can cause confusion regarding the types of the variables and their initial values. If more than one variable is declared in a declaration, care must be taken that the type and initialized value of the variable are handled correctly.
Though you can declare a variable multiple times in your C program, it can be defined only once in a file, a function, or a block of code.
E2238 Multiple declaration for 'identifier' (C++)An identifier was improperly declared more than once. This error might be caused by conflicting declarations, such as: int a; double a; A function declared in two different ways. A label repeated in the same function.
Only x is a pointer to int; y and z are regular ints.
This is one aspect of C declaration syntax that trips some people up. C uses the concept of a declarator, which introduces the name of the thing being declared along with additional type information not provided by the type specifier. In the declaration
int* x, y, z; the declarators are *x, y, and z (it's an accident of C syntax that you can write either int* x or int *x, and this question is one of several reasons why I recommend using the second style). The int-ness of x, y, and z is specified by the type specifier int, while the pointer-ness of x is specified by the declarator *x (IOW, the expression *x has type int).
If you want all three objects to be pointers, you have two choices. You can either declare them as pointers explicitly:
int *x, *y, *z; or you can create a typedef for an int pointer:
typedef int *iptr; iptr x, y, z; Just remember that when declaring a pointer, the * is part of the variable name, not the type.
185
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
