How can I shorten many while loops?

This is one of my first attempts to use Java and I tried my best, but I need to shorten it so it’s not so long.

Important is that it keeps all the coins of the Euro. It’s a German code so geld means money.

This part of the code System.out.println(rgeldt + " mal 2 Euro"); just means how often the 2 euros have to be ejected.

public static void Rueckgaberechner(Double geld) {
    System.out.println("Rueckgeld: ");
    int rgeldt = 0;
    while (geld >= 200) {
        geld = geld - 200;
        rgeldt = rgeldt + 1;
    }
    if (rgeldt >= 1) {
        System.out.println(rgeldt + " mal 2 Euro");
    }
    int rgeldO = 0;
    while (geld >= 100) {
        geld = geld - 100;
        rgeldO = rgeldO + 1;
    }
    if (rgeldO >= 1) {
        System.out.println(rgeldO + " mal 1 Euro");
    }
    int rgeldf = 0;
    while (geld >= 50) {
        geld = geld - 50;
        rgeldf = rgeldf + 1;
    }
    if (rgeldf >= 1) {
        System.out.println(rgeldf + " mal 50 Cent");
    }
    int rgeldtw = 0;
    while (geld >= 20) {
        geld = geld - 20;
        rgeldtw = rgeldtw + 1;
    }
    if (rgeldtw >= 1) {
        System.out.println(rgeldtw + " mal 20 Cent");
    }
    int rgeldten = 0;
    while (geld >= 10) {
        geld = geld - 10;
        rgeldten = rgeldten + 1;
    }
    if (rgeldten >= 1) {
        System.out.println(rgeldten + " mal 10 Cent");
    }
    int rgeldfive = 0;
    while (geld >= 5) {
        geld = geld - 5;
        rgeldfive = rgeldfive + 1;
    }
    if (rgeldfive >= 1) {
        System.out.println(rgeldfive + " mal 5 Cent");
    }
    int rgeldtwo = 0;
    while (geld >= 2) {
        geld = geld - 2;
        rgeldtwo = rgeldtwo + 1;
    }
    if (rgeldtwo >= 1) {
        System.out.println(rgeldtwo + " mal 2 Cent");
    }
    int rgeldone = 0;
    while (geld >= 1) {
        geld = geld - 1;
        rgeldone = rgeldone + 1;
    }
    if (rgeldone >= 1) {
        System.out.println(rgeldone + " mal 1 Cent");
    }
}

Answer

You can put it into a own function:

public static void Rueckgaberechner(Double geld) {
    System.out.println("Rueckgeld: ");
    geld = anzahlRueckgeld(200,geld, " mal 2 Euro");
    geld = anzahlRueckgeld(100,geld, " mal 1 Euro");
    geld = anzahlRueckgeld(50,geld, " mal 50 cent");
    geld = anzahlRueckgeld(20,geld, " mal 20 cent");
    geld = anzahlRueckgeld(10,geld, " mal 10 cent");
    geld = anzahlRueckgeld(5,geld, " mal 5 cent");
    geld = anzahlRueckgeld(2,geld, " mal 2 cent");
    anzahlRueckgeld(1,geld, " mal 1 cent");
}

public static  double anzahlRueckgeld(int amount, double geld ,String text) {
    int rgeldt =0;
    
    while (geld >= amount) {
        geld = geld - amount;
        rgeldt = rgeldt + 1;
    }
    if (rgeldt >=1) {
        System.out.println(rgeldt +text);
    }
    return geld;
}

BTW: By convention, method names in java should start with lower case character