c++作业代码

#include<iostream>
using namespace std;

void fun() {
	static int a = 1;
	int i= 5;
	i++;
	a++;
	cout << "i" << i << "a"<<a<<endl;
}
int main()
{
	fun();
}

 

#include <iostream>
using namespace std;
const float PI = 3.1459;
class Circle {
public:
	Circle(float r);
	float getArea();
private:
	float radius;
};
Circle::Circle(float r) {
	radius = r;
}
float Circle::getArea() {
	float area = PI*radius*radius;
	return  area;
}
int main() {
	Circle cir(10);
	cout << cir.getArea() << endl;

	
	return 0;
}

 

#include<iostream>
using namespace std;
class R {
public:
	R(int r1, int r2) :r1(r1), r2(r2) {}
	void print();
	void print() const;//声明常函数


private:
	int r1, r2;

};
void R::print() {
	cout << "r1=" << r1 << "r2=" << r2 << endl;
}
void R::print() const {
	cout << "const r1=" << r1 << "r2=" << r2 << endl;

}
int main() {
	R a(5, 4);
	a.print();
	R const b(20, 52);//常对象
	b.print();

	return 0;
}

#include <iostream>
using namespace std;
void RowSum(int a[][4],int nrow){
	for (int i = 0; i < nrow; i++) {
		int sum = 0;
		for (int j = 0; j < 4; j++)
		{
			sum = 0;
			sum += a[i][j];
		}
		cout << "sum" << i << sum << endl;
		a[i][0] = sum;
	}


}
int main() {
	int table[3][4] = { {1,2,3,4},{2,3,4,5},{3,4,5,6} };
	for (int i = 0; i < 3; i++)
	{	
		for (int j= 0; j < 4; j++)
		{
			
		}
		a[i] = i * 2 - 1;
		b[10 - i - 1] = a[i];

	}
	for (int i = 0; i < 10; i++)
	{
		cout << "a[]"<<a[i] <<"b[]"<< b[i] << endl;

	}
}

 

#include<iostream>
#include"标头.h"
#include<cmath>
using namespace std;
float lineFit( Point points[], int nPoint) {
	float avgX = 0, avgY = 0;
	float lxx = 0, lyy = 0, lxy = 0;
	for (int i = 0; i < nPoint; i++)
	{
		avgX += points[i].getX() / nPoint;
		avgY += points[i].getY() / nPoint;
	}
	for (int i = 0; i < nPoint; i++) {
		lxx += (points[i].getX() - avgX)*(points[i].getX() - avgX);
		lyy+= (points[i].getY() - avgY)*(points[i].getY() - avgY);
		lxy+= (points[i].getX() - avgX)*(points[i].getY() - avgY);
	}
	cout << "this line can be fitted by y=ax+b:" << endl;
	cout << "a=" << lxy / lxx << ":";
	cout << "b=" << avgY - lxy*avgX / lxx << ":";
	return lxy / sqrt(lxx*lyy);
}
int main() {
	Point p[10] = { Point(6,10),Point(14,20),Point(26,30),Point(75,80),Point(84,90),Point(33,40),Point(46,50),Point(54,60),Point(67,70),Point(100,100) };
	float r = lineFit(p, 10);
	cout << "line coefficient r=" << r << endl;
	return 0;
}

 

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

class Point
{
public:
	Point(int x = 0, int y = 0) :x(x),y(y){}

	int getX() { return x; }
	int getY() { return y; }
	friend float dist(Point&p1, Point&p2);

private:
	int x, y;
};
float dist(Point&p1, Point&p2) {
	double x = p1.x - p2.x;
	double y = p1.y - p2.y;
	return sqrt(x*x + y*y);
}

int main() {
	Point p1(1, 1);
	Point p2(4, 5);
	cout << dist(p1, p2) << endl;
}

 

 

#include <iostream>
using namespace std;

class Base1 {
public	:
	Base1(int i) { cout << "Constructing Basel" << i << endl; }
	~Base1() {
		cout << "Destructing Basel"  << endl;
	}
};

class  Base2 {
public:
	Base2(int j) { cout << "Constructing Base2" << j << endl; }
	~Base2() {
		cout << "Destructing Base2" << endl;
	}
};

class  Base3 {
public:
	Base3() { cout << "Constructing Base3" << endl; }
	~Base3() {
		cout << "Destructing Base3" << endl;
	}
};

class Derived :public Base2, public Base1, public Base3 {
public:
	Derived(int a,int b,int c,int d):Base1(a),member2(d),member1(c),Base2(b){}
private:
	Base1 member1;
	Base2 member2;
	Base3 member3;
};
//int fun(int x[10], int n) { return sizeof(x); }
int main() {
	Derived obj(1, 2, 3, 4);
	
}

 

#include<iostream>
using namespace std;
//多继承同名函数
class B1 {
public:
	int nV;
	void fun() { cout << "Member of B1" << endl; }
};

class B2 {
public:
	int nV;
	void fun() { cout << "Member of B2" << endl; }

};

class D1: public B1, public B2{
public:
	int nV;
	void fun() { cout << "member of D1" << endl; }

};

int main() {
	D1 d1;
	d1.nV = 1;
	d1.fun();
	d1.B1::nV = 2;
	d1.B1::fun();
	d1.B2::nV = 3;
	d1.B2::fun();
}