Execute an objects method without making a new instance -

how can execute print within testobject?

class program {     private int value;     static void main()     {         testobject test = new testobject();         program p1 = new program();         program p2 = new program();         p1.value = 1;         p2.value = 2;         p1.print();         p2.print();     }       private void print()     {         console.write(value.tostring());         console.readkey();     } }  class testobject {     // how execute p1.print here? } 

there multiple ways this:

pass program directly testobject

pros:

• simple change

cons:

• you have make print public
• you expose other things in program
• you're coupling testobject program directly

here's sample code:

class program {     static void main()     {         testobject test = new testobject(this);     }       public void print()     {         console.write(value.tostring());         console.readkey();     } }  class testobject {     public testobject(program p)     {         p.print();     } } 

pass delegate testobject

pros:

• simple change
• doesn't have make print public
• only exposes 1 method testobject

cons:

• the coupling testobject wants something, not testobject wants access something

here's sample code:

class program {     static void main()     {         testobject test = new testobject(() => print());     }       private void print()     {         console.write(value.tostring());         console.readkey();     } }  class testobject {     public testobject(action print)     {         print();     } } 

implement interface in program , pass testobject

pros:

• only exposes interface exposes
• easier implement other places (better "need interface" "needs delegate", clearer contract specification)
• no coupling specific type, coupling any object meets criteria - implements interface

cons:

• none relevant (in opinion)

here's sample code:

interface iprintable {     void print(); }  class program : iprintable {     static void main()     {         testobject test = new testobject(this);     }       public void print()     {         console.write(value.tostring());         console.readkey();     } }  class testobject {     public testobject(iprintable p)     {         p.print();     } } 

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conclusion: advice pick interface way. clearer design, easier extend without having multiple delegates being passed around.