網頁設計第十週練習筆記

請寫出一個具有『加、減、內積、負』的向量物件？ (Vector, add, sub, dot, neg)

class Vector 
{
    constructor(array)
    {
        this.a = array
    }
    add(f)
    {
        var r = []
        var s = this
        for (var i = 0; i < s.a.length; i++)
        {
            r[i] = s.a[i] + f.a[i]
        }
        return new Vector(r)
    }
    sub(f)
    {
        var r = []
        var s = this
        for (var i = 0; i < s.a.length; i++) 
        {
            r[i] = s.a[i] - f.a[i]
        }
        return new Vector(r)
    }
    dot(f) 
    {
        var r = []
        var s = this
        var k = 0
        for (var i = 0; i < s.a.length; i++) 
        {
            r[i] = s.a[i] * f.a[i]
            k = k + r[i]
        }
        return k
    }
    neg() 
    {
        var r = []
        var s = this
        for (var i = 0; i < s.a.length; i++) 
        {
            r[i] = s.a[i] * (-1)
        }
        return new Vector(r)
    }
  }
  
  var x = new Vector([1, 2, 3])
  var y = new Vector([1, 1, 1])
  console.log("x.add(y)=", x.add(y))
  console.log("x.sub(y)=", x.sub(y))
  console.log("x.dot(y)=", x.dot(y))
  console.log("x.neg()=", x.neg())