Why do you not declare several variables of the same type on the same line?

Question

Why is it bad practice to declare variables on one line?

e.g.

private String var1, var2, var3

instead of:

private          


        

Answer 1

In C/C++, you also have the problem that the * used to indicate a pointer type only applies to the directly following identifier. So a rather common mistake of inexperienced developers is to write

int* var1, var2, var3;

and expecting all three variables to be of type 'int pointer', whereas for the compiler this reads as

int* var1;
int var2;
int var3;

making only var1 a pointer.