Knowledge of C ++ preliminary study notes ----------

C ++ is based on an expansion on the C language, which not only contains the features of the C language, and optimized in C language, making an already complicated content easier.
C ++ three characteristics:

• Abstraction and encapsulation - classes and objects
• Inheritance and derivation
• Polymorphism

Next, we first discuss some simple basics ++ C:
1. On the:

2. function default parameters:

Experiment 1:
Write a function of circular, rectangular, triangular area, requirements for function overloading to achieve. Triangle area calculated using Heron's formula.

#include<iostream>
#include<math.h>
using namespace std;
#define PI 3.14

double  area(int r)
{
return PI*r*r;
}

double area(int a,int b)
{
	return a*b;
}

double area(int q,int w,int e)
{
	double p;
	p=(q+w+e)/2;
	return sqrt(p*(p-q)*(p-w)*(p-e));
}
//同一个函数名area实现三个不同的功能：
int main()
{
	double c,t;
	int r,a,b,q,w,e;
	cout<<"请输入圆的半径：";
		cin>>r;
		c=area(r);
	cout<<"圆的面积是："<<c<<endl;
	cout<<"请输入长方形的长和宽";
		cin>>a>>b;
	r=area(a,b);
    cout<<"当长方形的长和宽是："<<a<<"和"<<b<<"时，长方形的面积是；"<<r<<endl;
	cout<<"请输入三角形的三边长";
	    cin>>q>>w>>e;
    t=area(q,w,e);
	cout<<"当三角形的三边长shi："<<q<<"和"<<w<<"和"<<e<<"时，三角形的面积是："<<t<<endl;
	system("pause");
	return 0;
}

Experiment 2:
preparation of a program, to find two or three largest number of positive integers. Requirements: have a function with default parameters to achieve.

#include<iostream>
#include<math.h>
using namespace std;

int max(int a,int b=2)
{
	return a>b?a:b;
}
int main()
{
	int a,b=3;
    cout<<max(a=4,b)<<endl;
	return 0;
}

3. Quote:

4.new/delete operator: