Q:

Sytax issues for a Java beginner

I am a beginner in Java and I had an assignment to write a program which sells tickets. I have some issues that I can't really understand why they are wrong. The issues I have are in compiling.
import acm.program.*;
import acm.graphics.*;

public class tickets extends ConsoleProgram {
    public static double eisitirio = 1.2;
    public void run(){
    double nomisma=readInt("Insert coins and then press 0");
    boolean synthiki=false;
    double poso=0;
    while (synthiki=false){
        while (nomisma != 0){
            if ((nomisma==0.1)||(nomisma==0.2)||(nomisma==0.5)||(nomisma==1)||(nomisma==2)||(nomisma==5)){
            poso=poso+nomisma;
            }else {
                printIn("You did not insert a supported coin, please insert another one");
            }
            nomisma=readInt("Insert coins and then press 0");
        }
        if (poso < eisitirio){
            printIn("You did not insert enough money, please insert more coins");
        }else {
            synthiki=true;
        }
    }
    printIn("Here is your ticket");
    poso=poso-eisitirio;
    double resta=0;
    if ((poso/5) > 0){
        printIn("You have change: 5 euros");
        poso = poso-5;
    }
    if ((poso/2) > 0){
        printIn("You have change: 2 euros");
        poso = poso-2;
    }
    if ((poso/1) > 0){
        printIn("You have change: 1 euros");
        poso = poso-1;
    }   
    if ((poso/0.5) > 0){
        printIn("You have change: 50 cents");
        poso = poso-0.5;
    }
    if ((poso/0.2) > 0){
        printIn("You have change: 20 cents");
        poso = poso-0.2;
    }
    if ((poso/0.1) > 0){
        printIn("You have change: 10 cents");
        poso=poso-0.1;
    }
    }

}

Compiling errors: 
C:\Users\kriton\Desktop\Java>javac -cp acm.jar tickets.java
tickets.java:15: error: cannot find symbol
                                printIn("You did not insert a supported coin, please insert another one");
                                ^
  symbol:   method printIn(String)
  location: class tickets
tickets.java:20: error: cannot find symbol
                        printIn("You did not insert enough money, please insert more coins");
                        ^
  symbol:   method printIn(String)
  location: class tickets
tickets.java:25: error: cannot find symbol
        printIn("Here is your ticket");
        ^
  symbol:   method printIn(String)
  location: class tickets
tickets.java:29: error: cannot find symbol
                printIn("You have change: 5 euros");
                ^
  symbol:   method printIn(String)
  location: class tickets
tickets.java:33: error: cannot find symbol
                printIn("You have change: 2 euros");
                ^
  symbol:   method printIn(String)
  location: class tickets
tickets.java:37: error: cannot find symbol
                printIn("You have change: 1 euros");
                ^
  symbol:   method printIn(String)
  location: class tickets
tickets.java:41: error: cannot find symbol
                printIn("You have change: 50 cents");
                ^
  symbol:   method printIn(String)
  location: class tickets
tickets.java:45: error: cannot find symbol
                printIn("You have change: 20 cents");
                ^
  symbol:   method printIn(String)
  location: class tickets
tickets.java:49: error: cannot find symbol
                printIn("You have change: 10 cents");
                ^
  symbol:   method printIn(String)
  location: class tickets
9 errors

I don't know, I've tried a lot of things, but they seem really weird. I don't understand why the first if is wrong, I looked it up in the book, about ifs and booleans, but it seems correct that way.

A:

For starters, it's System.out.println for the printIn you have there. 
readInt should probably be changed to:
BufferedReader br = new BufferedReader( new InputStreamReader( System.in ) );

System.out.print( "Insert coins and then press 0" );
nomisma = Integer.parseInt( br.readLine() );
// This is the PURE implementation of the function you want; now, if you haven't defined this somewhere, it will cause you problems.

A:

error: cannot find symbol

means that...
... a symbol cannot be found.
The reason of this is...
... that a symbol is not defined.
Possible solutions:

define the symbol
use a defined symbol instead

In your case, you are trying to call a method, with the name of printIn. In our case, the symbol is printIn. Since this is not defined, you receive the error mentioned above. You either define the symbol like this:
public static void printIn(text) {
    System.out.println(text);
}

or use System.out.println instead. Read more here.

