GO接口实现多态

package main
 
import (
    "fmt"
)
 
type Income interface {
    calculate() int
    source() string
}
 
type FixedBilling struct {
    projectName  string
    biddedAmount int
}
 
type TimeAndMaterial struct {
    projectName string
    noOfHours   int
    hourlyRate  int
}
 
type Advertisement struct {
    adName     string
    CPC        int
    noOfClicks int
}
 
type yx struct {
    masterName string
    house int
    money int
}
 
func (fb FixedBilling) calculate() int {
    return fb.biddedAmount
}
 
func (fb FixedBilling) source() string {
    return fb.projectName
}
 
func (tm TimeAndMaterial) calculate() int {
    return tm.noOfHours * tm.hourlyRate
}
 
func (tm TimeAndMaterial) source() string {
    return tm.projectName
}
 
func (a Advertisement) calculate() int {
    return a.CPC * a.noOfClicks
}
 
func (a Advertisement) source() string {
    return a.adName
}
 
func (man yx) source() string {
    return man.masterName
}
 
func (man yx) calculate() int {
    return man.house * man.money
}
 
 //新增类型不用修改计算方法，直接在类型上实现接口
func calculateNetIncome(ic []Income) {
    var netincome int = 0
    for _, income := range ic {
        fmt.Printf("Income From %s = $%d\n", income.source(), income.calculate())
        netincome += income.calculate()
    }
    fmt.Printf("Net income of organisation = $%d", netincome)
}
 
func main() {
    project1 := FixedBilling{projectName: "Project 1", biddedAmount: 5000}
    project2 := FixedBilling{projectName: "Project 2", biddedAmount: 10000}
    project3 := TimeAndMaterial{projectName: "Project 3", noOfHours: 160, hourlyRate: 25}
    bannerAd := Advertisement{adName: "Banner Ad", CPC: 2, noOfClicks: 500}
    popupAd := Advertisement{adName: "Popup Ad", CPC: 5, noOfClicks: 750}
    jarvis := yx{masterName:"jarvis", house:8, money:10}
    incomeStreams := []Income{project1, project2, project3, bannerAd, popupAd, jarvis}
    calculateNetIncome(incomeStreams)
}