I am coding a small game for my amusement and I’m having an issue with getting a variable to be changed in one class from a value in another. I have actually done this in another class that wasn’t the main. The error I am getting when running is that I need main() to be main(String[] args) which I changed to main(int wgold).
import java.io.*;
class player {
public static void main (String[] args) throws IOException { // <<<<<<<<<<<<<<<<<<<<< Need to have this get the value sent
String Name, cmd;
int gold, quit, spaces, weint, randGold;
gold = 0;
cmd = "none";
quit = 0;
spaces = 0;
weint = 0;
/* Ideas for new commands:
attack - Attacks monster you have run into. - 100%
eat - Heals you. - 0%
run - Gets you away from a battle. - 100%
walk - Moves you one space and you can: find something (gold, food, ect...) or run into a monster. - 50%
*/
while (quit == 0) {
gold += wgold; // <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< This is the setting of the gold after the battle >>>>>>>>>>>>>>>>>>>>>>>
wgold = 0;
if (cmd.equalsIgnoreCase("none")) {
System.out.println("-------Commands-------n");
System.out.println("distance - Displays the amount of spaces you have walked.");
System.out.println("gold - Shows the amount of gold you have.");
System.out.println("quit - Exits the program.");
System.out.println("walk - Moves you one space.n");
System.out.println("--End of command list--n");
cmd = "wait";
BufferedReader stdin = new BufferedReader (new InputStreamReader (System.in));
System.out.print("Command: ");
System.out.flush();
cmd = stdin.readLine();
}
if (cmd.equalsIgnoreCase("gold")) {
System.out.println("nGold: " + gold + "n");
cmd = "none";
}else if (cmd.equalsIgnoreCase("walk")) {
spaces += 1;
weint = misc.random(1000); // Sets a random number out of 1000 for a percentage.
if ((weint >= 0) & (weint < 300)) {
enemies obj = new enemies();
obj.main();
cmd = "none";
} else if ((weint >= 300) & (weint < 500)) {
randGold = misc.random(10); // Sets the random amount of gold found while walking.
if (randGold <= 0) {
randGold = 1;
}
System.out.println("nYou have walked one space and found " + randGold + " gold piece(s).n");
gold += randGold;
cmd = "none";
} else if ((weint >= 500) & (weint <= 1000)) {
System.out.println("nYou have walked one space.n");
cmd = "none";
}
} else if (cmd.equalsIgnoreCase("distance")) {
System.out.println("nSpaces you have moved: " + spaces + ".n");
cmd = "none";
} else if (cmd.equalsIgnoreCase("quit")) {
System.out.println("Quitting the program...");
quit = 1;
} else {
System.out.println("nCommand not recognized.n");
cmd = "none";
}
}
}
}
class battle {
public static void main(String monster, int level, int mhp, int drop) throws IOException { // (String monster) gets the return value of the monster sent by the enemies class.
int end, hp, str, smhp, exp;
Long hit;
String cmd;
end = 0;
hp = 10;
str = 1;
exp = 0;
smhp = mhp;
cmd = "none";
System.out.println("nnn-------Battle!-------nnn");
System.out.println("You've encountered a wild " + monster + " level " + level + "!nn");
while(end == 0) {
if(cmd.equalsIgnoreCase("none")) {
System.out.println("----Commands----n");
System.out.println("attack - Attacks the enemy.");
System.out.println("run - Runs from battle.n");
System.out.println("--End of command list--nnn");
System.out.println("-----Status----n");
System.out.println("HP: " + hp + "/10");
System.out.println("Strength: " + str + "n");
System.out.println("---Wild " + monster + " stats---");
System.out.println("Wild " + monster + " HP: " + mhp + "/" + smhp + "n");
cmd = "wait";
BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Command: ");
System.out.flush();
cmd = stdin.readLine();
}
if(cmd.equalsIgnoreCase("run")) {
System.out.println("nYou have escaped from the battle!n");
end = 1;
} else if(cmd.equalsIgnoreCase("attack")) {
hit = Math.round(misc.random(str) * .7);
System.out.println("You hit: " + hit);
mhp -= hit;
if(hit >= 1) {
exp += hit * 12;
}
cmd = "none";
//Add HP for monsters / attack command. Not all here but you know where...
} else {
System.out.println("nCommand not recognized.n");
cmd = "none";
}
if(mhp <= 0) {
System.out.println("You have won!");
System.out.println("You found: " + drop + " coins!");
player obj = new player(); // <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< This is where the value is sent to the player class
obj.main(drop);
if(exp >= str * 80) {
str += 1;
System.out.println("Congradulations! You now have " + str + " strength.");
}
end = 1;
}
}
}
}
class enemies {
public static void main() throws IOException {
String monster;
int drop, level, mint, mhp;
mint = misc.random(10);
if (mint >= 7) {
monster = "Goblin";
} else {
monster = "Wizard";
}
battle obj = new battle(); // calls the battle class
level = misc.random(3); // Makes a random level for the enemy.
mhp = level + 3;
drop = misc.random(level);
if(drop <= 0) {
drop = 1;
}
drop = drop * 3;
obj.main(monster, level, mhp, drop); // sends the String monster to the battle class.
}
}
I know my code is a mess and there are probably a lot of things I could have done differently but I am just learning at the moment. Any help would be very appreciated.
This code is also available here: http://pastebin.com/kjuD3GJd
Answer
You need a reference to the instance to the Main class. Something along the following code scetch (will contain typos)
public class Main{
public static void main (String[] args){
new Main().start();
}
public void start(){
new OtherClass(this).doSomething();
}
public void whatever(){...}
}
public class OtherClass{
private final Main main;
public OtherClass(Main aMain){
main = aMain;
}
public void doSomething{
main.whatever();
}
}
Inside the whatever method you can access all the state of the Main instance. Of course you can pass parameters as well.
Regarding your other implicit question: To start a program you have to use a static void main(String[] args) method. Anything else wont work. Of course you can have arbitrary other methods including some with the same name, although I would recommend to use unique names for starters. This avoids the compiler confusing you about which method it is complaining.
As a an add-on some advice on asking questions here: Copy(*) your code to a fresh project. Then remove everything not necessary to understand your problem. In 9 out of 10 cases you’ll find the solution to your problem in the process. In the last case you have a code sample that people are actually looking at, resulting in much better answers.
(*) instead of copying the use of a version control system, e.g. is recommended, but I guess you are not there yet.