java - When to use a constant? -

java - When to use a constant? -

below code snippet of arraylist, either takes in 'initialcapacity' provided user or default of 10. question - why 10 not static constant ? guess constants used when variable repeated more 1 time in code. right ?

public arraylist(int initialcapacity) { super(); if (initialcapacity < 0) throw new illegalargumentexception("illegal capacity: "+ initialcapacity); this.elementdata = new object[initialcapacity]; } /** * constructs empty list initial capacity of ten. */ public arraylist() { this(10); }

constants used give names variables.

you phone call "default_initial_capacity"

a program, 1 can read story.

here code snippet example:

char * find_type(char *str,int *type){ str = trim_leading_space(str); if(*str == slash_sign){ str++; }else{ display_error(bad_type_format, str); } str = trim_leading_space(str); *type = convert_to_zero_or_one(str[0]); if(*type == no){ display_error(bad_type_format, str); }else { str++; } homecoming str; }

the code written in c, still proves point.

here definition of "bad_type_format"

#define bad_type_format 34

if had left 34, when came edit code, wouldn't know why wrote 34 in it. next index of error, long list of possible errors.

java constants