Algoritma :

Deskripsi

r                 : integer

luas              : float

Deklarasi

luas ß 3.14*r*r

write (luas)

Berikut programnya :

#include<iostream.h>

#include<conio.h>

void lingkaran()

{

  int r;

  cout<<"masukan nilai jari-jari : ";

  cin>>r;

  cout<<"Luas lingkaran = "<< 3.14*r*r<<endl;

}

int main() {

    lingkaran();

    return 0;

}

Program classnya :

#include <iostream.h>

#include <conio.h>

class luas {

friend istream& operator >> (istream&, luas&);

friend ostream& operator << (ostream&, const luas&);

public:

luas();

void hitung_luasnya(){ luas = 3.14*r*r;}

private:

    int r;

    float luas;

};

luas::luas(){

cout << "Program mencari luas lingkaran \n" << endl;

}

istream& operator >>(istream& cin, luas& masukan){

   cout << "Masukkan jari-jari : ";   cin >> masukan.r;

   cout<<endl;

return cin;

}

ostream& operator << (ostream& out, const luas& keluaran)

{

  out<< " Nilai jari- jari : " <<keluaran.r<<endl;

  out<< " Luas lingkaran = "<<keluaran.luas<<endl;

return out;

}

void main(){

  luas lingkaran;

  cin>>lingkaran;

  lingkaran.hitung_luasnya();

  cout<<lingkaran;

  getch();

}

Teman-teman juga bisa mendemokannya ke jeliot ,, check it out ....

Demo ke jeliot :

Fungsi Menghitung Luas Lingkaran

import jeliot.io.*;

public class luas {

public static void main()

{

     int r ;

     float luas;

     System.out.print("Masukan jari-jari : ");

     r = Input.readInt();

    

     luas = (float)3.14*r*r;

     System.out.print("Luas lingkaran = ");

     System.out.print(luas);

 }

}

Explanation:
The above program is a program to calculate the area of ​​a circle by using the function. Which program would invoke the functionality. In this program using a variable r and spacious. The program will do the counting process with a predetermined formula. After users input the value of r the area of ​​a circle will appear.

Algoritma :

Deskripsi

AB               : float

x1,x2,y1,y2     : float

Deklarasi

AB = sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2))

write (a,b)

Berikut programnya :

#include <iostream.h>

#include <conio.h>

#include <math.h>

class jarak {

friend istream& operator >> (istream&, jarak&);

friend ostream& operator << (ostream&, const jarak&);

public:

jarak();

void hitung(){

     AB = sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2));

};

private:

    float x1,y1,x2,y2;

    float AB;

};

jarak::jarak(){

cout << "mencari jarak antara titik A(x1,y1) dan B(x2,y2)\n" << endl;

}

istream& operator >>(istream& cin, jarak& masukan){

   cout << "Nilai titik A " <<endl;

   cout << "Masukkan nilai x1 : ";   cin >> masukan.x1;

   cout << "Masukkan nilai y1 : ";   cin >> masukan.y1;

   cout << "Nilai titik B " <<endl;

   cout << "Masukkan nilai x2 : ";   cin >> masukan.x2;

   cout << "Masukkan nilai y2 : ";   cin >> masukan.y2;

   cout<<endl;

return cin;

}

ostream& operator << (ostream& out, const jarak& keluaran)

{

  out<< "jarak antara titik tersebut adalah : " <<keluaran.AB<<endl;

return out;

}

void main(){

jarak titik;

cin>>titik;

titik.hitung();

cout<<titik;

getch();

}

Explanation:
In this program just like the program to find the midpoint of the program but find the distance between two points is point A (x1, y1) and point B (x2, y2). Here also using variable x1, x2, y1 and y2 but the difference only variable AB. To find the distance of two points by using the formula  AB = sqrt ((x1-x2) ² + (y1-y2) ²). After getting input from the user initializes the program will work with the formula specified in the program.

Algoritma :

Deskripsi

a,b      : integer

Deklarasi

    if ( a > b )

       then

              write(a)

else

then

              write(b)

endif

Berikut programnya :

#include <iostream.h>

#include <conio.h>

class terbesar{

friend istream& operator >> (istream&, terbesar&);

friend ostream& operator << (ostream&, const terbesar&);

public:

terbesar();

void bandingkan(){

     if (a > b)

        cout<< " Bilangan terbesar : "<<a;

     else

        cout<< " Bilangan terbesar : "<<b<<endl;

};

private:

     int a,b;

};

terbesar::terbesar(){

cout << "menentukan bilangan terbesar dari yang diinputkan\n" << endl;

}

istream& operator >>(istream& cin, terbesar& masukan){

     cout<<"masukan bilangan pertama : ";

     cin>>masukan.a;

     cout<<"masukan bilangan kedua : ";

     cin>>masukan.b;

     cout<<endl;

return cin;

}

ostream& operator << (ostream& out, const terbesar& keluaran){

     out<< " inilah yang terbesar "<<endl;

return out;

}

void main(){

terbesar bilangan;

cin>>bilangan;

bilangan.bandingkan();

cout<<bilangan;

getch();

}

Explanation:
At this time I wanted to try the program to find the largest number of 2 numbers are entered. Which of these programs use the election if ... else that is a> b. Seletah user input values ​​a and b values​​, the program will work by using the election to seek the greatest value of these two numbers are entered.