javascript - 在 Javascript 中集成嵌套的 for 和 if 循环时遇到问题

Question

我正在尝试运行图书馆 checkin / checkout 系统的模拟。我已经制作了所有对象，但执行模拟本身的循环遇到了问题。我的代码:

伪代码:

//while loop or for loop for 90 days
      //For loop over catalog
         //forloop over patrons 
             //Check if available , if so check book out
             //If not available check book back in
                 //check checking back in check to see if book is overdue and if so add a fine
    //When down loop over patrons to see their fees

我在该循环中的尝试

for (var j = 0; j < 90; j++) {            
    for (var i = 0; i < catalog.length; i++) {
        for (var k = 0; k < patrons.length; k++) {
            if (books[k].Available = true) {
                books[k].checkOut = true; }
                else {
                    books[k].Available = true;
                }
                if (books[k].isOverdue = true) {
                    fine = fine + 5.00;
                }
            }
        }
        patrons[j].fine = fine;
        j++;
    }

所有代码

    var Book = function(title, Available, publicationDate, checkoutDate, callNumber, Authors) {
    this.title = title;
    this.Available = Available;
    this.publicationDate = publicationDate;
    this.checkoutDate = checkoutDate;
    this.callNumber = callNumber;
    this.Authors = Authors;
};

var Author = function(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
};

var Patron = function(firstName, lastName, libCardNum, booksOut, fine) {
    this.firstName = firstName;
    this.lastName = lastName;
    this.libCardNum = libCardNum;
    this.booksOut = booksOut;
    this.fine = fine;
};

Book.prototype.checkOut = function() {
    this.Available = false;
    var temp = new Date(1000000000);
    var date = new Date() - temp;
    var res = new Date(date);
    this.checkoutDate = res;
};

Book.prototype.isOverdue = function() {
    var singleDay = 1000 * 60 * 60 * 24;
    var todayDate = new Date().getTime();
    var difference = todayDate - this.checkoutDate.getTime();
    if (Math.round(difference / singleDay) >= 14) {
        return true;
    }
    return false;
};

Patron.prototype.read = function(book) {
    this.booksOut.add(book);
}

Patron.prototype.read = function(book) {
    this.booksOut.remove(this.booksOut.length);
}

var authors = [];
authors[0] = new Author("Auth", "One");
authors[1] = new Author("AutL", "Two");

var catalog = [];
catalog[0] = new Book('Bk1', true, new Date(2001, 1, 21), new Date(), 123456, authors);
catalog[1] = new Book('Bk2', true, new Date(2002, 2, 22), new Date(), 987656, authors);
catalog[2] = new Book('Bk3', true, new Date(2003, 3, 23), new Date(), 092673, authors);
catalog[3] = new Book('Bk4', true, new Date(2004, 4, 24), new Date(), 658342, authors);
catalog[4] = new Book('Bk5', true, new Date(2005, 5, 25), new Date(), 345678, authors);

var patrons = [];
patrons[0] = new Patron('Pat1', 'Wat', 1, catalog, 0.00);
patrons[1] = new Patron('Pat2', 'Wot', 1, catalog, 0.00);
patrons[2] = new Patron('Pat3', 'Wit', 1, catalog, 0.00);
patrons[3] = new Patron('Pat4', 'Wet', 1, catalog, 0.00);
patrons[4] = new Patron('Pat5', 'Wut', 1, catalog, 0.00);

var j = 0;

//while loop or for loop for 90 days
  //For loop over catalog
     //forloop over patrons 
         //Check if available , if so check book out
         //If not available check book back in
             //check checking back in check to see if book is overdue and if so add a fine
//When down loop over patrons to see their fees

for (var j = 0; j < 90; j++) {            
    for (var i = 0; i < catalog.length; i++) {
        for (var i = 0; i < patrons.length; i++) {
            if (books[i].Available = true) {
                books[i].checkOut = true; }
                else {
                    books[i].Available = true;
                }
                if (books[i].isOverdue = true) {
                    fine = fine + 5.00;
                }
            }
        }
        patrons[j].fine = fine;
        j++;
    }

for (i = 0; i < patrons.length; i++) {
    console.log(patrons[i].firstName + " has checked out the following books:");
    for (j = 0; j < patrons[i].booksOut.length; j++) {
        console.log(patrons[i].booksOut[j].title);
    }
    console.log(patrons[i].firstName + " has fine amount: $" + patrons[i].fine);
}

Answer 1

在代码中更改重复的变量名称 i 并且不要忘记添加 var 以免它们成为全局变量:

for (var j = 0; j < 90; j++) {            
    for (var i = 0; i < catalog.length; i++) {
        for (var n = 0; n < patrons.length; n++) {
            if (books[n].Available = true) {
                books[n].checkOut = true; }
                else {
                    books[n].Available = true;
                }
                if (books[n].isOverdue = true) {
                    fine = fine + 5.00;
                }
            }
        }
        patrons[j].fine = fine;
        j++;
    }

for (var i = 0; i < patrons.length; i++) {
    console.log(patrons[i].firstName + " has checked out the following books:");
    for (var j = 0; j < patrons[i].booksOut.length; j++) {
        console.log(patrons[i].booksOut[j].title);
    }
    console.log(patrons[i].firstName + " has fine amount: $" + patrons[i].fine);
}