#include <iostream>

using namespace std;

void luas_lingkaran (float jari)
{
	float hasil = 3.14 * (jari * jari);
	cout << endl;
	cout << "Rumus luas lingkaran = phi(3.14 atau 22/7) * jari * jari" << endl;
	cout << endl;
	cout << "Luas lingkaran = " << hasil << endl;
}

float keliling_lingkaran (float jari)
{
	float tambah = jari + jari;
	float keliling = 3.14 * tambah;
	return keliling;
}

int main()
{
	int pilih;
	float r, luas, keliling, tum, phi = 3.14;
	
	menu:
	cout << "PROGRAM DEV C++ LUAS DAN KELILING LINGKARAN\n" << endl;
	cout << "| | | | | | | | | | | | | | | | | | | | | |" << endl;
	cout << "v v v v v v v v v v v v v v v v v v v v v v" << endl;
	cout << "===========================================" << endl;
	cout << "   Silahkan pilih menu di bawah ini!" << endl;
	cout << "===========================================\n" << endl;
	cout << "1.Program Menghitung Luas Lingkaran" << endl;
	cout << "2.Program Menghitung Keliling Lingkaran" << endl;
	cout << "3.Exit Program" << endl;
	cout << endl;
	cout << "Masukkan Pilihan : ";
	cin >> pilih;
	cout << endl;
	system ("cls");
	
	if (pilih == 1)
	{
		cout << "========================" << endl;
		cout << "|Program Luas Lingkaran|" << endl;
		cout << "========================" << endl;
		cout << endl;
		cout << "Masukkan jari-jari lingkaran : ";
		cin >> r;
		luas_lingkaran(r);
		cout << endl;
		cout << "[ Tekan enter untuk kembali ke menu ]" << endl;
		system ("cls");
		goto menu;
	}
	else if (pilih == 2)
	{
		cout << "============================" << endl;
		cout << "|Program Keliling Lingkaran|" << endl;
		cout << "============================" << endl;
		cout << endl;
		cout << "Masukkan jari-jari lingkaran : ";
		cin >> r;
		cout << endl;
		cout << "Rumus keliling lingkaran = 2 * phi * jari\n" << endl;
		cout << "Keliling lingkaran = " << keliling_lingkaran (r) << endl;
		cout << endl;
		cout << "[ Tekan enter untuk kembali ke menu ]" << endl;
		system ("cls");
		goto menu;
	}
	else if (pilih == 3)
	{
		cout << "=================================" << endl;
		cout << "===>||  PROGRAM SELESAI  ||<<<===" << endl;
		cout << "=================================" << endl;
		cout << endl;
		cout << "PROGRAM BY DEDE WAHYU ANUGRAH" << endl;
		return 0;
	}
	else
	{
		cout << "Inputan yang anda masukkan salah! Tekan enter untuk kembali" << endl;
		system ("cls");
		goto menu;
	}
}

C++ Online Compiler

Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!

Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}