Methods(function) & Method Overloading(function overloading) in java

  Program to add to numbers using function

package com.company;

public class functionINjava {
    static int add(int x, int y)
    {
        int c= x+y;
        return c;
    }
    public static void main(String[] args) {
        int a =1;
        int b=2;
        int c1=add(a,b);
        System.out.println(c1);
    }
}

program to print a value using function

package com.company;

public class functionOVERLOADING {
    static void str()
    {
        System.out.println("hy, I'm Vishal Rana:");
    }

    public static void main(String[] args) {
        str();
    }
}

program to print an array using function (call by reference)

package com.company;

public class functionOVERLOADING {
    static void num (int [] str)
    {
       str[0]=23;
    }

    public static void main(String[] args) {
     int [] ar={4,678,8,33,7,9,0};
     num(ar);
        System.out.println(ar[0]);
    }
}

program with function overloading:

remember that void in function definition can not be changed during function overloading, the only thing that changes during the function overloading is  function parameters.

package com.company;

public class functionOVERLOADING {
    static void num ()
    {
        System.out.println("here is function overloading");
    }
    static void  num(int a,int b)
    {
        int c=a+b;
        System.out.println(c);
    }
    static void  num(float  ax,float by)
    {
        float c1=ax+by;
        System.out.println(c1);
    }
    public static void main(String[] args) {
        num();

        num(5,6);

        num(1.2f,3.8f);
    }
}

vararg function argument passing technique

package com.company;
public class varargs {

    static int vrg (int ...a)            //here a will work as an ARRAY
    {
        int c=0;
        for (int v:a)
        { c += v ;
        }
        return c;
    }
    //now user must pass a argument in the function
    static int vr (int x,int ...a)
    {
        int c=x;
        for (int v:a)
        { c += v ;
        }
        return c;
    }

    public static void main(String[] args) {
        System.out.println("the sum is "+ vrg(1,5,8,4,7,1,7,1));
        System.out.println("the 2nd type of sum is"+ vr(5,3,4,7,7,8,9,43,32,54,8,9));
    }
}

program to illustrate the concept of recursion in java

package com.company;

public class recursion {
    static int rec(int n)
    {
        if(n==0 ||n==1)
        {
            return 1;
        }
        else {
            return n* rec(n-1);
        }
    }

    public static void main(String[] args) {
        int n=4;
        System.out.println(rec(n));
    }
}

program to print a multiplication table using function

package com.company;
public class multiplicationtableusingjava {
    static void mul(int n)
    {
        for(int i=0; i<=10; i++)
        { int m=n*i;
            System.out.printf("\n %d * %d = %d",n,i,m);
        }
    }

    public static void main(String[] args) {
        int n=2;
        int i=1;
        mul(2);    }
}

program to print a triangle using function

package com.company;

public class triangleusingfunction {
    static void ma()
    {
        int a=5;
        for (int i=0; i<=5; i++)
        {
            System.out.println("\n");
            for(int j=0;j<=i;j++) {
                System.out.print("\t *");
            }
        }
    }
    public static void main(String[] args) {
       ma();
    }
}

program to print a triangle using recursion

package com.company;
public class recursion_triangle {
    static int rec(int n)
    {
        if(n==1)
        {
            return 1;
        }
        else {
            for (int i=0;i<=n; i++)
            {
                System.out.println("\n");
                for(int j=0;j<=i;j++)
                {
                    System.out.print("\t *");
                }
            }
            return (n-1);
        }
    }
    public static void main(String[] args) {
        rec(5);
    }
}