Note:Call to this() must be the first statement in constructor.

Java Programming Language Class, Object and Methods in java (Article) Class, Object and Methods in java (Program)

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Program:

 class Studentclass{
int rollno;
String name,course;
float age;

Studentclass(int rollno,String name,String course){
this.rollno=rollno;
this.name=name;
this.course=course;
}

Studentclass(int rollno,String name,String course,float age){
this.age=age;
this(rollno,name,course);//Compile Time Error: Call to this must be first statement in constructor
}

void display(){
	System.out.println(rollno+" "+name+" "+course+" "+age);
	}
}

class MainClassOfStudent{
public static void main(String args[]){

	Studentclass obj1=new Studentclass(111,"RAHIM","C");
	Studentclass obj2=new Studentclass(112,"RAM","java",21.5f);
	obj1.display();
	obj2.display();
	}
}

/*
Note: Call to this() must be the first statement in constructor.
otherwise it will give Compile Time Error:
*/

Output:

C:\Users\Rumman Ansari\Documents\MainClassOfStudent.java:14: error: call to this must be first statement in constructor
this(rollno,name,course);//Compile Time Error: Call to this must be first statement in constructor
    ^
1 error

Explanation:

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