Constructor shows undefined output ?

Question

In contact manager app output is displayed but undefined is mentioned.

Answer 1

Javascript

Answer 2

function contact(name, number){
this.name = name;
this.number = number;
this.print =output;
}

var a = new contact("David", 12345);
var b = new contact("Amy", 987654321);

function output()
{
console.log(this.name, ":",this.number);

//console.log(b.name,":",b.number);

}
console.log(a.print());
console.log(b.print());