Final answer:
The primary job of a constructor is to initialize instance variables of a new object in object-oriented programming. It is not to alter, display, or return the value of instance variables, those tasks are performed by other methods.
Step-by-step explanation:
The primary job of a constructor in object-oriented programming is to initialize instance variables when a new object of a class is created. It sets up the initial state of the object by assigning values to the instance variables. This can default to zero or null, or it can be specific values provided as parameters to the constructor.
Here's a very basic example of a constructor in Java:
public class Example {
private int value;
public Example(int initialValue) {
value = initialValue; // Constructor initializes 'value' with 'initialValue'
}
}
When you create a new instance of 'Example' like this: Example obj = new Example(10);, the constructor is called, setting the 'value' to 10. This illustrates that the constructor's role is initialization, not altering values after they have been set (that's a job for setters), displaying them (job for getters or other methods), or returning values (which can't be done directly from a constructor).