如何解决如果满足 while 条件则退出循环
我有一个将用户输入存储在数组中的程序。 每次存储用户输入时，int var Counter 都会增加 1。 我的问题是，如果我存储 25 个变量，循环结束但可以说我输入了无效的内容，即使在存储了 25 个变量之后，循环也会继续。我想确保循环在满足 while 条件后结束，即使程序捕获了错误，如果有任何意义。
不，我想使用数组而不是列表！
谢谢
void AddPassenger()
{
//Counts total passengers on the bus to determin if the buss is empty
Passenger.TotalPassengers = 0;
//Variable for loops
int Counter = 0;
do
{
//Adds 25 passengers with a loop
for (int i = 0; i < Passenger.Age.Length; i++)
{
Console.Clear();
Logo();
Console.WriteLine("\nEnter Age for passenger {0}",Counter + 1);
Counter++;
try
{
Passenger.Age[i] = Convert.ToInt32(Console.ReadLine());
}
catch
{
Console.WriteLine("Did you enter a number?\n");
Console.WriteLine("Press any key to try again...");
Counter--;
Console.ReadKey();
break;
}
//Checks if user enters a valid age
if (Passenger.Age[i] < 0 || Passenger.Age[i] > 130)
{
Console.WriteLine("Try a different age");
}
Console.WriteLine("\nEnter Gender for passenger {0}",Counter);
Console.WriteLine("1) Male");
Console.WriteLine("2) Female");
Console.WriteLine("3) Other");
//Using a temp variable to run switch for selecting gender
int temp = 0;
try
{
temp = Convert.ToInt32(Console.ReadLine());
Console.Clear();
Passenger.TotalPassengers++;
}
catch
{
Console.Clear();
Logo();
Console.WriteLine("\nNot a valid choice");
}
switch (temp)
{
case 1:
Passenger.Gender[i] = "Male";
break;
case 2:
Passenger.Gender[i] = "Female";
break;
case 3:
Passenger.Gender[i] = "Other";
break;
default:
Console.WriteLine("Did you enter a number?\n");
Console.WriteLine("Press any key to try again...");
Console.ReadKey();
Counter--;
break;
}
}
} while (Counter < 25);
这不应该发生
解决方法
在您的问题范围内，您可以执行以下类似操作（请注意，这尚未运行，但很快就收到了评论）
void AddPassenger()
{
//Counts total passengers on the bus to determin if the buss is empty
Passenger.TotalPassengers = 0;
//Variable for loops
int Counter = 0;
do
{
//Adds 25 passengers with a loop
for (int i = 0; i < Passenger.Age.Length; i++)
{
// ensure we're not leaving the scope of the `while`
if(Counter >= 25)
break;
Console.Clear();
Logo();
Console.WriteLine("\nEnter Age for passenger {0}",Counter + 1);
try
{
Passenger.Age[i] = Convert.ToInt32(Console.ReadLine());
}
catch
{
Console.WriteLine("Did you enter a number?\n");
Console.WriteLine("Press any key to try again...");
Console.ReadKey();
break;
}
//Checks if user enters a valid age
if (Passenger.Age[i] < 0 || Passenger.Age[i] > 130)
{
Console.WriteLine("Try a different age");
break; // you needed to break here I assume
}
Console.WriteLine("\nEnter Gender for passenger {0}",Counter);
Console.WriteLine("1) Male");
Console.WriteLine("2) Female");
Console.WriteLine("3) Other");
//Using a temp variable to run switch for selecting gender
int temp = 0;
try
{
temp = Convert.ToInt32(Console.ReadLine());
Console.Clear();
Passenger.TotalPassengers++;
}
catch
{
Console.Clear();
Logo();
Console.WriteLine("\nNot a valid choice");
break; // you needed to break here I assume
}
switch (temp)
{
case 1:
Passenger.Gender[i] = "Male";
break;
case 2:
Passenger.Gender[i] = "Female";
break;
case 3:
Passenger.Gender[i] = "Other";
break;
default:
Console.WriteLine("Did you enter a number?\n");
Console.WriteLine("Press any key to try again...");
Console.ReadKey();
break;
}
Counter++; //move counter to here to only increment at the end if successful
}
} while (Counter < 25);
但是，我要么更改 Passenger 的名称，要么更改模型本身，因为尚不清楚为什么 Passenger 有一个年龄或性别数组。当然，每个乘客都应该是拥有这些字段的自己的实体，不是吗？
类似于：
public Bus
{
public Passenger[] Passengers { get; set; }
public int TotalPassengers { get; set; }
}
public Passenger
{
public int Age { get; set; }
public string Gender { get; set; }
}
应该重新考虑 while 中的 for 循环。以这种方式嵌套循环没有意义。
这里有 2 个循环，一个 for 循环和一个 do-while 循环。 for 循环仅在 i 达到数组的限制时停止，而 do-while 循环仅在 Counter 达到 25 时停止。
您提到即使存储了 25 个变量，循环仍会继续。这是因为每次有无效输入时，for 循环都会从 0 重新开始。将 int i = 0 换成 int i = Counter，这样，它会从停止的地方继续。
另外：
您不需要 2 个循环，特别是 for 循环。您可以删除它，然后将所有提及的 i 替换为 Counter，break 与 continue 相同。 （结合@Tubs 的回答）在这种情况下您也不需要 if(Counter >= 25) break;。这样做有效地合并了 2 个循环，而不是具有相同功能的 2 个循环。
Console.WriteLine("\nEnter Gender for passenger {0}",Counter); 不会将 1 添加到 Counter，这将导致 Enter Gender for passenger 0。
扩展@Tubs 的回答：
此外， Counter 仅在所有 break 之后递增，这意味着它无法访问。您必须转移到每个成功案例（1、2 和 3）。
生成的代码是：
void AddPassenger()
{
//Counts total passengers on the bus to determin if the buss is empty
Passenger.TotalPassengers = 0;
//Variable for loops
int Counter = 0;
//Adds 25 passengers with a loop
do
{
Console.Clear();
Logo();
Console.WriteLine("\nEnter Age for passenger {0}",Counter + 1);
try
{
Passenger.Age[i] = Convert.ToInt32(Console.ReadLine());
}
catch
{
Console.WriteLine("Did you enter a number?\n");
Console.WriteLine("Press any key to try again...");
Console.ReadKey();
continue;
// Continue while loop instead of breaking it
}
//Checks if user enters a valid age
if (Passenger.Age[i] < 0 || Passenger.Age[i] > 130)
{
Console.WriteLine("Try a different age");
continue;
// Continue while loop instead of breaking it
}
Console.WriteLine("\nEnter Gender for passenger {0}",Counter + 1);
Console.WriteLine("1) Male");
Console.WriteLine("2) Female");
Console.WriteLine("3) Other");
//Using a temp variable to run switch for selecting gender
int temp = 0;
try
{
temp = Convert.ToInt32(Console.ReadLine());
Console.Clear();
Passenger.TotalPassengers++;
}
catch
{
Console.Clear();
Logo();
Console.WriteLine("\nNot a valid choice");
continue;
// Continue while loop instead of breaking it
}
switch (temp)
{
case 1:
Passenger.Gender[i] = "Male";
// Increment after success
Counter++;
continue;
// Continue while loop instead of breaking it
case 2:
Passenger.Gender[i] = "Female";
// Increment after success
Counter++;
continue;
// Continue while loop instead of breaking it
case 3:
Passenger.Gender[i] = "Other";
// Increment after success
Counter++;
continue;
// Continue while loop instead of breaking it
default:
Console.WriteLine("Did you enter a number?\n");
Console.WriteLine("Press any key to try again...");
Console.ReadKey();
continue;
// Continue while loop instead of breaking it
}
} while (Counter < 25);
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