Vector-2D(for homework)

Vector-2D(for homework)

标签（空格分隔）： 程序设计实验 c++

本人学院

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Description:

Please create a class Vector.

The declaration of Vector is in ‘Vector.h’

before programing, you should revise the operations between vectors.

note:

add() vecter1 + vecter2

sub() vecter1 - vecter2

rev() means reverse of the vector like (1, 2) -> (-1, -2);

dot_product() 点乘；

cross_product() 叉乘（返回 int，使用abs函数取绝对值）；

print() display the vecter in the form like “(1, 2)\n”;

main.cpp

#include <iostream>
#include "Vector.h"
using namespace std;

int main() {
    // test#
    int x1, y1, x2, y2;
    cin >> x1 >> y1 >> x2 >> y2;
    Vector vec1(x1, y1);
    Vector vec2(x2, y2);
    Vector vec3 = vec1.add(vec2);
    vec3.print();
    Vector vec4 = vec1.sub(vec2);
    vec4.print();
    Vector vec5 = vec1.inverse();
    vec5.print();
    int dot_result = vec1.dot_product(vec2);
    cout << "dot product equal:" << dot_result << ".\n";
    int cross_result = vec1.cross_product(vec2);
    cout << "cross product equal:" << cross_result << ".\n";

    return 0;
}

Vector.h

#ifndef VECTOR_H
#define VECTOR_H
using namespace std;

class Vector {
    public:
        // constructer
        Vector();
        Vector(int, int);
        // copy constructer
        Vector(const Vector &otherVec);
        // destructer
        ~Vector() {}
        // vecter1 + vecter2
        Vector add(Vector);
        // vecter1 - vecter2
        Vector sub(Vector);
        // -vecter1
        Vector inverse();
        // vecter1 * vecter2
        int dot_product(Vector);
        // vecter1 x vecter2
        int cross_product(Vector);
        void print();
    private:
        int x, y;
};

#endif

读题

my answer

#include<iostream>
#include<cmath>
#include"Vector.h"

using namespace std;

Vector::Vector() {
    x = 0;
    y = 0;
}
Vector::Vector(int newX, int newY) {
    x = newX;
    y = newY;
}

// copy constructer
Vector::Vector(const Vector &otherVec) {
    x = otherVec.x;
    y = otherVec.y;
}

// vecter1 + vecter2
Vector Vector::add(Vector v) {
    Vector other;
    other.x = x + v.x;
    other.y = y + v.y;
    return other;
}

// vecter1 - vecter2
Vector Vector::sub(Vector v) {
    Vector other;
    other.x = x - v.x;
    other.y = y - v.y;
    return other;
}

// -vecter1
Vector Vector::inverse() {
    Vector v;
    v.x = 0 - x;
    v.y = 0 - y;
    return v;
}

// vecter1 * vecter2
int Vector::dot_product(Vector v) {
    return x * v.x + y * v.y;
}

// vecter1 x vecter2
int Vector::cross_product(Vector v) {
    double pro = static_cast<double>(x * v.y - y * v.x);
    int ans = static_cast<int>(abs(pro));
    return ans;
}

void Vector::print() {
    cout << "(" << x << ", " << y << ")" <<endl;
}

the standard answer

#include "Vector.h"
#include <iostream>
#include <stdlib.h>
using namespace std;

Vector::Vector() {
    x = y = 0;
}

Vector::Vector(int a, int b) {
    x = a;
    y = b;
}

Vector::Vector(const Vector &otherVec) {
    x = otherVec.x;
    y = otherVec.y;
}

Vector Vector::add(Vector v) {
    return Vector(x+v.x, y+v.y);
}

Vector Vector::sub(Vector v) {
    return Vector(x-v.x, y-v.y);
}

Vector Vector::inverse() {
    return Vector(-x, -y);
}

int Vector::dot_product(Vector v) {
    return x*v.x+y*v.y;
}

int Vector::cross_product(Vector v) {
    return abs(x*v.y-y*v.x);
}

void Vector::print() {
    cout << "(" << x << ", " << y << ")\n";
}

反思

直接用构造函数返回成员