If Else輸出相同的結果

-1

對不起，再次打擾你，但我似乎有我的代碼的另一個問題。它爲某些輸入輸出相同的結果，我花了大約15分鐘時間試圖找出問題所在。我會問我的老師，但我現在不在大學。If Else輸出相同的結果

再次，代碼在下面，並感謝您花時間忍受我。

//declare vars and/or constants 
var endString = "Total cost per night is $"; 

//input vars 
pplCount = prompt("How many people will be staying?"); 
discYes = prompt("Do you have an AAA discount?"); 
viewYes = prompt("Do you want a room with a view?"); 

//if variables 
//double yes 

if(pplCount == "1" || pplCount == "2" && discYes == "Yes" && viewYes == "Yes") { 
    discount = 50*0.15; 
    roomCost = 50; 
    viewCost = (roomCost*0.10); 
    finalRoomCost = roomCost - discount + viewCost; 
    document.write(endString + finalRoomCost); 
} 
else if(pplCount === "3" || pplCount === "4" && discYes == "Yes" && viewYes == "Yes") { 
    discount = 60*0.10; 
    roomCost = 60; 
    viewCost = (roomCost*0.10); 
    finalRoomCost = roomCost - discount + viewCost; 
    document.write(endString + finalRoomCost); 
} 
else if(pplCount === "5" || pplCount === "6" && discYes === "Yes" && viewYes === "Yes") { 
    discount = 70*0.05; 
    roomCost = 70; 
    viewCost = (roomCost*0.10); 
    finalRoomCost = roomCost - discount + viewCost; 
    document.write(endString + finalRoomCost); 
} 
else if(pplCount === "1" || pplCount === "2" && discYes === "No" && viewYes === "Yes") { 
    discount = 50*0.15; 
    roomCost = 50; 
    viewCost = (roomCost*0.10); 
    finalRoomCost = roomCost + viewCost; 
    document.write(endString + finalRoomCost); 
} 
else if(pplCount === "3" || pplCount === "4" && discYes === "No" && viewYes === "Yes") { 
    discount = 60*0.10; 
    roomCost = 60; 
    viewCost = (roomCost*0.10); 
    finalRoomCost = roomCost + viewCost; 
    document.write(endString + finalRoomCost); 
} 
else if(pplCount === "5" || pplCount === "6" && discYes === "No" && viewYes === "Yes") { 
    discount = 70*0.05; 
    roomCost = 70; 
    viewCost = (roomCost*0.10); 
    finalRoomCost = roomCost + viewCost; 
    document.write(endString + finalRoomCost); 
} 
else if(pplCount === "1" || pplCount === "2" && discYes === "No" && viewYes === "No") { 
    finalRoomCost = 50; 
    document.write(endString + finalRoomCost); 
} 
else if(pplCount === "3" || pplCount === "4" && discYes === "No" && viewYes === "No") { 
    finalRoomCost = 60; 
    document.write(endString + finalRoomCost); 
} 
else if(pplCount === "5" || pplCount === "6" && discYes === "No" && viewYes === "No") { 
    finalRoomCost = 70; 
    document.write(endString + finalRoomCost); 
} 
else if(pplCount === "1" || pplCount === "2" && discYes === "Yes" && viewYes === "No") { 
    discount = 50*0.15; 
    roomCost = 50; 
    viewCost = (roomCost*0.10); 
    roomCost = roomCost - discount; 
    document.write(endString + finalRoomCost); 
} 
else if(pplCount === "3" || pplCount === "4" && discYes === "Yes" && viewYes === "No") { 
    discount = 60*0.10; 
    roomCost = 60; 
    finalRoomCost = roomCost - discount; 
    document.write(endString + finalRoomCost); 
} 
else if(pplCount === "5" || pplCount === "6" && discYes === "Yes" && viewYes === "No") { 
    discount = 70*0.05; 
    roomCost = 70; 
    finalRoomCost = roomCost - discount; 
    document.write(endString + finalRoomCost); 
}

來源

2013-04-17 minecraftModder

如果你確切地告訴使用哪個if-else對導致你的問題，它會非常有幫助。 –

只是想知道，但你爲什麼要在使用'=='和'==='之間切換。大概堅持'==='。 – Ian

給我們一個失敗的用例... – Populus

我想你的條件分組存在一些問題。所以請檢查你的條件，如下所示，我認爲這可能會解決你的問題。

if((pplCount === "1" || pplCount === "2") && (discYes === "Yes" && viewYes === "Yes")) 
{ 
...... 
...... 
} 
else if() 
{ 
}

來源

2013-04-17 17:18:11

那麼現在它不顯示任何輸出，嗯... – minecraftModder

@minecraftModder看到[this]（http://jsfiddle.net/XAsX3/）正在工作。我只是用你的代碼來演示工作條件。但是你應該爲你所有的if/elseif條件做到這一點。 –

的&&操作地結合不同於||更緊密，這意味着

if(pplCount == "1" || pplCount == "2" && discYes == "Yes" && viewYes == "Yes") {

被解釋爲

if(pplCount == "1" || ((pplCount == "2" && discYes == "Yes") && viewYes == "Yes")) {

因此，邏輯的該分支將被採用時「pplCount」是1，不管「discYes」和「viewYes」的值如何。

這就像普通的代數約定（紙和鉛筆，忘記JavaScript），其中乘法優先於加法。當你寫

2x + 5

然後每個人都知道你的意思是「乘以2 x，則加5」，而不是「加五到X，再乘上2」。

來源

2013-04-17 17:14:45 Pointy

（y）很好的描述給學生，而不僅僅是說_look into operator precedence_ – Ejaz

If Else輸出相同的結果

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