how do i use a forloop to increment array indices? In Java

Darktalyn1 · Post by **Darktalyn1** » Sat Oct 16, 2004 11:15 pm

i have a character array with 4 indices called

char[] pegs = new char[4];

i want to use a for loop that will go through and perform the same action on each of the indices

however when i type

for(pegs = 0; pegs <=3; pegs++){

//all the code goes in here

}

it tells me that im using incompatible types. So, i realize I'm not that much of a coder ... i guess i can see why it's not working - it's a character array, not int. The question is ... how do i do it then?!

Thanks in advance

fliptw · Post by **fliptw** » Sat Oct 16, 2004 11:21 pm

why do you want to use chars arrays? Java does have a String object you know.

anyways, you can't increments arrays, which is what pegs++ is doing, but pegs[i++](where i is an int), incrementing the index of the array is perfectly legal.

something like:

Code: Select all

for(int i =0; i<=3; i++){
pegs[i]='l';
...
}

read thru the API documentation, you'll lots of nifty stuff.

Grendel · Post by **Grendel** » Sat Oct 16, 2004 11:22 pm

Pegs is your pointer to the data -- you need an index variabl like

cahr[] pegs = new char[4] ;

for ( int i = 0 ; i <=3 ; ++i )
{
pegs = ... ;
}

Note: the for ( int i .. is C++ syntax dunno if java will do it. Split it out of the for if not.

DCrazy · Post by **DCrazy** » Sat Oct 16, 2004 11:33 pm

Grendel, Java's Array objects are not the same thing as C/C++ arrays, in that they are not pointers to blocks of memory. They are actual objects (Java.lang.Array). Java will do the int i = 0; in the for loop, but I'm not entirely sure that it has the prefix increment operator (++i). Just as valid to use i++ anyway.

Darktalyn1 · Post by **Darktalyn1** » Sun Oct 17, 2004 9:53 am

Hey thanks guys you're right. that did work ! Now I just have to figure out how to use the forloop with a modulo operator...

fliptw · Post by **fliptw** » Sun Oct 17, 2004 1:24 pm

the modulus operator returns the remainder of the division of two integers. so 5 % 2 would return 1, and 4 % 2 would return 0.

you are pretty much walking thru each of the indexes of the pegsMatched array, so you can condense those three blocks of code into one loop.

DCrazy · Post by **DCrazy** » Sun Oct 17, 2004 2:08 pm

This is one of those Mastermind games, isn't it? You have to guess a code of four colored pegs, and it tells you which ones are in the right spot, which ones are out of place, and which ones aren't even in the code?