How to call another components function in angular2

I have two components as follows and I want to call a function from another component. Both components are included in the third parent component using directive.

Component 1:

@component(
    selector:'com1'
)
export class com1{
    function1(){...}
}

Component 2:

@component(
    selector:'com2'
)
export class com2{
    function2(){...
        // i want to call function 1 from com1 here
    }
}

I've tried using @input and @output but I don't understand exactly how to use it and how to call that function, can anyone help?

If com1 and com2 are siblings you can use

@component({
  selector:'com1',
})
export class com1{
  function1(){...}
}

com2 emits an event using an EventEmitter

@component({
  selector:'com2',
  template: `<button (click)="function2()">click</button>`
)
export class com2{
  @Output() myEvent = new EventEmitter();
  function2(){...
    this.myEvent.emit(null)
  }
}

Here the parent component adds an event binding to listen to myEvent events and then calls com1.function1() when such an event happens. #com1 is a template variable that allows to refer to this element from elsewhere in the template. We use this to make function1() the event handler for myEvent of com2:

@component({
  selector:'parent',
  template: `<com1 #com1></com1><com2 (myEvent)="com1.function1()"></com2>`
)
export class com2{
}

For other options to communicate between components see also component-interaction