1.3.1_methods_functions.md

1. Methods/Functions in Java-

Syntax-
 return_type method_name(arg1,arg2,.....)
                     {
                     }

• arguments arg1, arg2, arg3,.... are optional.

• return_type is the data type of the variable returned by the method or it can be void if the method does not return anything.

• Example

public class Test {
   public static void main(String[] args) {
      Test t = new Test();

      t.add_nums();            // Call to the method
   }

   public void add_nums() {
      int i = 10;
      int j = 15;
      int k = i + j;
      System.out.println("k:" + k);
   }
}
  

int add_nums()
             {
                  int i=10;
                  int j=15;      
                  int k=i+j;       
                  return k;
             }

       int n= add_nums();            // Call to the method
      System.out.println("n:" + n);   

void add_nums(int i, int j)
             {
                  int k=i+j;       
                 System.out.println("k:" + k);   
             }

       add_nums(10,15);            // Call to the method

int add_nums(int i, int j)
             {                  
                  int k=i+j;       
                  return k;
             }

       int n= add_nums(10,15);            // Call to the method
       System.out.println("n:" + n);   

Method overloading-

• With method overloading, multiple methods can have the same name with different parameters.

Example-

void add_nums(); void add_nums(int i);

void add_nums(char i); // valid method

void add_nums(int i, int j); void add_nums(String i, int j);

// return type doesn’t play any role here **void add_nums(); and int add_nums(); will throw error. **

Method overriding

• Method overriding is used with classes when a child class has the same method as the parent class. Which means, overriding happens when a child class has its own implementation of a method which is also declared/implemented in the parent class.