我想要做的是设置透支限额，即-150，如果他们的余额为-150，则用户不能再提取。我的代码如下：
提款方法
public void Withdraw(double amount){
if (amount + 5 > balance ){ //If amount and transaction fee is greater than balance then apply for overdraft
System.out.println("Insufficent funds");
System.out.println("Would you like to apply for an ovedraft?");
System.out.println("1:Yes");
System.out.println("2:No, return me back to menus");
Choice = Option.nextLine();
if (Choice.equalsIgnoreCase("1")){
if((balance = balance - amount+5)<=-150){ //If balance is grater than 150 , apply for overdraft
System.out.println("You have exceeded your Overdraft Limit, you will now be returned back to the menus");
return;
}
else{ //if not exceeding bank balance
balance -= amount + 5;
System.out.println("You have withdrawen £" + amount);
System.err.println("You now have a balance of £" +balance);
return;
}
}
}
}
它们都在同一个类中，即“帐户”，现在发生的是消息确实发生 - （“您已超出透支限额，现在将返回菜单”）并返回菜单，但当我去检查余额时，钱仍然扣除，并显示超过-150的余额，例如。 -190我怎样才能确保-150是限制而不是扣除。希望这个问题得到理解。
答案 0 :(得分：4)
问题在于：
if (!IsPostBack)
{
// your logic here
}
这里的关键是if ((balance = balance - amount + 5) <= -150) {
。这是在支票
这样的事情可以避免这个问题。
=注意使用 if (balance - amount - 5 < 0) {
System.out.println("Insufficent funds");
System.out.println("Would you like to apply for an ovedraft?");
System.out.println("1:Yes");
System.out.println("2:No, return me back to menus");
Choice = Option.nextLine();
if (Choice.equalsIgnoreCase("1")) {
if (balance - amount - 5 <= -150) {
System.out.println("You have exceeded your Overdraft Limit, you will now be returned back to the menus");
} else { //if not exceeding bank balance
balance -= amount + 5;
System.out.println("You have withdrawen £" + amount);
System.err.println("You now have a balance of £" + balance);
}
进行数学和比较的更明确的计算（if (balance - amount - 5 <= -150)）。这在口头上更容易理解。
答案 1 :(得分：2)
function uploadFile_multipart (foldername, filename) {
var xmlhttp = new XMLHttpRequest();
xmlhttp.onload = function() {
var contentType = xmlhttp.getResponseHeader('Content-Type');
var contentLength = xmlhttp.getResponseHeader('Content-Length');
var contentData = new Uint8Array(xmlhttp.response);
const boundary = 'foo_bar_baz';
var multipartRequestBody = '--' + boundary + '\r\nContent-Type: application/json; charset=UTF-8\r\n\r\n' +
'{ "name": "' + filename + '", "mimeType": "' + contentType + '" }\r\n\r\n--' + boundary +
'\r\nContent-Type: ' + contentType + '\r\n\r\n' +
contentData + '\r\n--' + boundary + '--';
var request = gapi.client.request({
'path': '/upload/drive/v3/files',
'method': 'POST',
'params': {'uploadType': 'multipart'},
'headers': {'Content-Type': 'multipart/related; boundary=' + boundary, 'Content-Length': contentLength},
'body': multipartRequestBody
});
request.execute(function(resp) { alert(resp); });
}
xmlhttp.open("GET", foldername + filename, true);
xmlhttp.responseType = "arraybuffer";
xmlhttp.send();
}
是你的问题。首先，您没有在括号内写if((balance = balance - amount+5)<=-150)，因此它应该是amount+5。
其次，您实际上是在这里更改余额（amount-5是分配运算符）。您还写了=而不是<=。你应该写的是以下内容：
<
答案 2 :(得分：0)
除上述所有答案外，我将添加此内容：
如果我有 1 $ 且我透支 50 $ ，那么我的帐户可以在
1 $ -55 $ = -54 $
但是这种情况不可能
if (amount + FEES > balance) { // If amount and transaction fee is greater than balance then apply for overdraft
System.out.println("Insufficent funds");