我在代码中循环if语句时遇到问题。我查看了stackoverflow上的其他线程，但我无法多次使用它。我试图创建的程序是铸造公司的基本转换器。我尝试做的是使用户可以输入所需的转换类型，然后输入蜡的重量。然后它将为使用者提供正确数量的贵金属克。问题是我需要它从一开始就运行直到用户完成使用它。我尝试使用while语句，但它只是循环if语句的else部分。这是我的参考代码：
static void Main(string[] args)
{
double waxWeight, bronzeWeight, silverWeight, fourteenkGoldWeight,
eighteenkGoldWeight, twentytwokGoldWeight, platinumWeight;
string wW;
bool doesUserWantToLeave = false;
Console.WriteLine("Please specify the type of conversion you would like to accomplish:"
+ "\n(Bronze, Silver, 14k Gold, 18k Gold, 22k Gold, Platinum, or Exit):");
string conversionType = Console.ReadLine();
//bool B = conversionType == "Bronze";
//bool S = conversionType == "Silver";
//bool ftG = conversionType == "14k Gold";
//bool etG = conversionType == "18k Gold";
//bool ttG = conversionType == "22k Gold";
//bool P = conversionType == "Platinum";
while (!doesUserWantToLeave)
{
if (conversionType == "Bronze")
{
Console.WriteLine("What is the weight of the wax model?");
wW = Console.ReadLine();
waxWeight = double.Parse(wW);
bronzeWeight = waxWeight * 10;
Console.WriteLine("You need " + bronzeWeight + " grams of bronze.");
Console.ReadLine();
}
else if (conversionType == "Silver")
{
Console.WriteLine("What is the weight of the wax model?");
wW = Console.ReadLine();
waxWeight = double.Parse(wW);
silverWeight = waxWeight * 10.5;
Console.WriteLine("You need " + silverWeight + " grams of silver.");
Console.ReadLine();
}
else if (conversionType == "14k Gold")
{
Console.WriteLine("What is the weight of the wax model?");
wW = Console.ReadLine();
waxWeight = double.Parse(wW);
fourteenkGoldWeight = waxWeight * 13.5;
Console.WriteLine("You need " + fourteenkGoldWeight + " grams of 14 Karat gold.");
Console.ReadLine();
}
else if (conversionType == "18k Gold")
{
Console.WriteLine("What is the weight of the wax model?");
wW = Console.ReadLine();
waxWeight = double.Parse(wW);
eighteenkGoldWeight = waxWeight * 15;
Console.WriteLine("You need " + eighteenkGoldWeight + " grams of 18 Karat gold.");
Console.ReadLine();
}
else if (conversionType == "22k Gold")
{
Console.WriteLine("What is the weight of the wax model?");
wW = Console.ReadLine();
waxWeight = double.Parse(wW);
twentytwokGoldWeight = waxWeight * 17.3;
Console.WriteLine("You need " + twentytwokGoldWeight + " grams of 22 Karat gold.");
Console.ReadLine();
}
else if (conversionType == "Platinum")
{
Console.WriteLine("What is the weight of the wax model?");
wW = Console.ReadLine();
waxWeight = double.Parse(wW);
platinumWeight = waxWeight * 21.5;
Console.WriteLine("You need " + platinumWeight + " grams of platinum.");
Console.ReadLine();
}
else if (conversionType == "Exit")
{
doesUserWantToLeave = true;
}
else
{
Console.WriteLine("Sorry! That was an invalid option!");
Console.ReadLine();
}
}
}
我意识到一个优秀的程序员并没有两次输入相同的代码，但我还没有达到那个级别，我只想让代码循环。我是否必须将它作为一个大的嵌套if语句？
答案 0 :(得分：5)
您只需要一次金属类型。移动两行，在while循环中提示并接收用户输入：
while (!doesUserWantToLeave)
{
Console.WriteLine("Please specify the type of conversion you would like to accomplish:"
+ "\n(Bronze, Silver, 14k Gold, 18k Gold, 22k Gold, Platinum, or Exit):");
string conversionType = Console.ReadLine();
if (conversionType == "Bronze")
{
...
你提到你是编程新手并且意识到你在重复自己。您正确地优先考虑使代码首先工作。这很好。有了它的工作，你应该看看改进代码。
首先，在每个if之后重复以下三行，因此只需在循环顶部询问一次：
Console.WriteLine("What is the weight of the wax model?");
wW = Console.ReadLine();
waxWeight = double.Parse(wW);
接下来，每个if中的最后两行主要重复，但唯一更改的部分（金属名称）是已知的。所以它们都可以被删除，并在循环结束时只用一个副本替换：
Console.WriteLine("You need " + metalWeight + " grams of {0}.",
conversionType.ToLower());
Console.ReadLine();
然后每if只留下一行。它也会重复，所需的值可以存储在Dictionary中。做到这一切，你最终可能得到一个解决方案：
static void Main(string[] args)
{
bool userWantsToStay = true;
var conversions = new Dictionary<string, double>
{
{ "Bronze", 10.0 },
{ "Silver", 10.5 },
{ "14k Gold", 13.5 },
{ "18k Gold", 15.0 },
{ "22k Gold", 17.3 },
{ "Platinum", 21.5 }
};
while (userWantsToStay)
{
Console.WriteLine("Please specify the type of conversion you would like to accomplish:");
Console.WriteLine("(Bronze, Silver, 14k Gold, 18k Gold, 22k Gold, Platinum, or Exit):");
var metalType = Console.ReadLine();
Console.WriteLine("What is the weight of the wax model?");
var wW = Console.ReadLine();
var waxWeight = double.Parse(wW);
if (conversions.ContainsKey(metalType))
{
var metalWeight = waxWeight * conversions[metalType];
Console.WriteLine("You need {0} grams of {1}.", metalWeight, metalType.ToLower());
Console.ReadLine();
}
else if (metalType == "Exit")
{
userWantsToStay = false;
}
else
{
Console.WriteLine("Sorry! That was an invalid option! Try again");
Console.ReadLine();
}
}
}
这可以进一步改进（许多ReadLines可能会被删除;你没有在解析之前测试权重输入是否是有效的双倍），但它会让你在正确的路径上。< / p>
答案 1 :(得分：3)
你必须在循环结束时重新分配用户选项，否则它永远不会改变：
while (!doesUserWantToLeave)
{
if (conversionType == "Bronze")
{
//....
}
// ...
else if (conversionType == "Exit")
{
doesUserWantToLeave = true;
}
else
{
Console.WriteLine("Sorry! That was an invalid option!");
}
conversionType = Console.ReadLine();
}
因此您还必须删除循环中的所有其他Console.ReadLine();。您也可以使用break代替离开循环的doesUserWantToLeave = true。
答案 2 :(得分：-1)
您可以将这段代码提取为一个单独的方法，该方法将在主程序的循环中调用，请参阅下面的伪代码：
public void Main(string[] args)
{
while(!doesUserWantToLeave) {
Console.WriteLine("Please specify the type of conversion you would like to accomplish:"
+ "\n(Bronze, Silver, 14k Gold, 18k Gold, 22k Gold, Platinum, or Exit):");
string conversionType = Console.ReadLine();
Console.WriteLine("What is the weight of the wax model?");
double waxWeight = double.Parse(Console.ReadLine());
double weight = ConvertMethod(conversionType, waxWeight);
Console.WriteLine(string.Format("You need {0} grams of {1}.", weight, conversionType));
}
}
该方法如下所示。可以传递字符串，也可以使用枚举来定义转换类型。
public double ConvertMethod(string type, double weight)
{
switch(type) {
case "Silver":
return weight * 10.5;
case "Bronze":
return weight * 10;
// etc...
}
}