Exercise:
Write a Java Program to call one constructor from another.
Click Here to View the Solution!
public class CallConstructor {
int sum;
// first constructor
CallConstructor() {
this(
19,
11);
//calling second constructor
}
// second constructor
CallConstructor (
int arg1,
int arg2) {
this.sum = arg1 + arg2;
// adding two integers
}
void display() {
System.out.println(
"Sum = " + sum);
}
// Driver main class
public static void main(String[] args) {
// call the first constructor as it has no parameters
CallConstructor obj =
new
CallConstructor ();
obj.display();
}
}
Click Here to View the Output!
Sum = 30
Click Here to View the Explanation!
- This program is used to call a constructor from another constructor within the same class.
- A class
CallConstructor
is created which holds the two constructorsCallConstructor()
andCallConstructor(int arg1, int arg2)
. - The first constructor calls the second constructor by using the keyword
this
as follows:this.(19, 11)
. - The second constructor uses the values provided by the first constructor to perform the operation
sum = arg1 + arg2
and display the sum. - It is to be noted, the first line of the constructor calling the second constructor should be the one that calls the constructor i.e. the first line of the
CallConstructor()
constructor should bethis.(19, 11)
.