Classes and Objects in C++
practice.

#include <iostream>
#include <complex>
using namespace std;
int main()
{
   complex<double> c1(4.0,3.0);
   cout << "c1: " << c1;
   complex<float> c2(polar(5.0,0.75));
   cout << c1 + complex<double>(c2.real(),c2.imag());
   return 0;
}

#include <iostream>
using namespace std;
int main()
{
    int x;
    int *p;
    x = 5;
    p = &x;
    cout << *p;
    return 0;
}

#include <iostream>
using namespace std;
int main()
{
    int i;
    enum month 
    {
        JAN,FEB,MAR,APR,MAY,JUN,JUL,AUG,SEP,OCT,DEC
    };
    for (i = JAN; i <= DEC; i++)
        cout << i;
    return 0;
}

#include <iostream>
using namespace std;
int main()
{
    int a, b;
    int* c;
    c = &a;
    a = 200;
    b = 200;
    *c = 100;
    b = *c;
    cout << *c << " " << b;
    return 0;
}

#include <iostream>
#include <string>
using namespace std;
 
class A
{
	static int a;
 
   public:
	void change(int i){
		a = i;
	}
	void value_of_a(){
		cout<<a;
	}
};
 
int main(int argc, char const *argv[])
{
	A a1 = A();
	a1.change(5);
	a1.value_of_a();
	return 0;
}

#include <iostream> 
#include <string>
using namespace std; 
int main(int argc, char const *argv[])
{
	string str;
	cin>>str;
	cout<<str;
	return 0;
}

#include <iostream>
using namespace std;
int main()
{
    double a = 21.09399;
    float b = 10.20;
    int c ;
    c = (int) a;
    cout << c ;
    c = (int) b;
    cout << c ;
    return 0;
}

#include <iostream>
#include <cstring>
using namespace std;
int main ()
{
    char str1[10] = "Hello";
    char str2[10] = "World";
    char str3[10];
    int  len ;
    strcpy( str3, str1);
    strcat( str1, str2);
    len = strlen(str1);
    cout << len << endl;
    return 0;
}

#include <iostream>
#include <string>
using namespace std;
class Box{
    int capacity;
public:
    Box(){}
    Box(double capacity){
	this->capacity = capacity;
    }
    bool operator<(Box b){
	return b.capacity < this->capacity? true : false;
    }
};
int main(int argc, char const *argv[])
{
    Box b1(10);
    Box b2 = Box(14);
     if(b1 < b2){
	cout<<"B1's capacity is small";
    }
    else{
	cout<<"B2's capacity is small";
    }
    return 0;
}

#include <iostream>
#include <string>
using namespace std;
class complex
{
    int i;
    int j;
    public:
    complex(){}
    complex(int a, int b)
    {
	i = a;
	j = b;
    }
    complex operator+(complex c)
    {
	complex temp;
	temp.i = this->i + c.i;
	temp.j = this->j + c.j;
	return temp;
    }
 void operator+(complex c)
    {
	complex temp;
	temp.i = this->i + c.i;
	temp.j = this->j + c.j;
	temp.show_poss();
    }
 void show(){
    cout<<"Complex Number: "<<i<<" + i"<<j<<endl;
    }
 void show_poss(){
    cout<<"Your result after addition will be: "<<i<<" + i"<<j<<endl;
    }
};
int main(int argc, char const *argv[])
{
    complex c1(1,2);
    complex c2(3,4);
    c1 + c2;
    return 0;
}