is #define in C similar to a static variable in Java?

Question

In C we can write:

#define LOWER 0

And in Java we can write:

static int lower = 0;

Don't these statements have the same purpose of letting other methods use the variable lower?

Answer 1

They are totally different. Define is more of a copy paste that the C preprocessor uses. Static is an attribute modifier for a Java class. A static attribute can be changed at runtime.

Answer 2

#define in C causes textual substitution. For example:

#define PI 3.14

...
a = PI * r * r;  // becomes: a = 3.14 * r * r

Now, the scope of #define is much larger than that; it isn't only limited to variables (and there isn't something directly equivalent in Java). When you have a static variable, there is no guarantee that that variable will not change, so a similar "textual substation" cannot be made. However, when you declare a static final variable and assign it to a compile-time constant, there is such a guarantee. So:

public static final double PI = 3.14;

...
a = PI * r * r;  // becomes: a = 3.14 * r * r, like in C

Much like what happened with #define, static final constants are replaced with their actual values at compile time. In this sense, static final constants are similar to #define constants.