我有以下代码可供使用。我在这里遇到的问题是代码在while循环中运行而不等待 String temp = Console.ReadLine（）行上的输入。需要帮助了解为什么以及如何修复请。提前谢谢！
/*Banker's algorithm Implementation*/
class Program
{
static void Main(string[] args)
{
int n = 0;//number of resources we will be dealing with
int proc_num = 0;//Total number of processes to share available resources
IDictionary<String, SysProcess> processes = new Dictionary<String, SysProcess>();
IDictionary<String, int> MaxR = new Dictionary<String, int>();// maximum available resources
IDictionary<String, int> avail = new Dictionary<String, int>();// Available resources after first allocation
Dictionary<String, int> availsum = new Dictionary<string, int>();
//Start
while (true)
{
Console.WriteLine(" What is number of resources to be shared? : ");
if (!int.TryParse(Console.ReadLine(), out n))
{
Console.WriteLine(" Error Please provide valid number --- {0}!", n);
}
else
{
break;
}
}
//get the maximum number of each Resources Ie Total Resources Available
while (true && n>0)
{
Console.WriteLine("Using a comma delimited list(e.g. 0, 0, 0, 0) list maximum of each of the {0} resources : ", n);
String temp;
temp = Console.ReadLine();
if (!String.IsNullOrEmpty(temp))
{
String[] maxR = temp.Split(',');
for (int a = 1; a <= n; a++)
{
MaxR.Add("Resource#" + a.ToString(), Convert.ToInt32(maxR[a]));
}
break;
}
}
while (true && n>0)
{
Console.Write("Enter total number of processes to share the available resources :");
if (!int.TryParse(Console.Read().ToString(), out proc_num))
{
Console.WriteLine(" Error Please provide valid number --- {0}!", proc_num);
}
else
{ break; }
}
if(proc_num > 0)
{
//Request Process Max and allocated resources data
for (int i = 1; i <= proc_num; i++)
{
Console.Write("Using a comma delimited list, Enter total number of Resources 1 through {0} are needed by PROCESS#{1} ?", n, i);
String[] temps = Console.ReadLine().Split(',');
SysProcess tempproc = new SysProcess("Process#" + i.ToString());
for (int a = 0; a < temps.Length; a++)
{
tempproc.Add_max_resource("Resource#" + (a + 1).ToString(), Convert.ToInt32(temps[a]));
}
//How many resources have already been allocated to each resource
temps = null;
Console.Write("Using a comma delimited list,Enter number of resources 1 through {0} already allocated to PROCESS#{1} ? ", n, i);
temps = Console.ReadLine().Split(',');
for (int a = 0; a < temps.Length; a++)
{
tempproc.add_alloc_resource("Resource#" + (a + 1).ToString(), Convert.ToInt32(temps[a]));
}
processes.Add("Process#" + i.ToString(), tempproc);
}
Console.WriteLine("Processing . . . ");
Console.WriteLine();
Console.WriteLine("Available resources ");
//Compute Available Resources
for (int i = 0; i < n; i++)
{
if (!availsum.ContainsKey("Resource#" + (i + 1).ToString()))
availsum.Add("Resource#" + (i + 1).ToString(), 0);
foreach (SysProcess sp in processes.Values)
{ //add sum up the available
availsum["Resource#" + (i + 1).ToString()] += sp.alloc_resources["Resource#" + (i + 1).ToString()];
}
}
//print out the availables we computed
Console.Write(" avail< ");
for (int j = 0; j < n; j++)
{
Console.Write(availsum["Resource#" + (j + 1).ToString()] + ",");
if (j + 1 == n)//if this is the last one, go ahead and output the rest
Console.Write("{0} > ", availsum["Resource#" + (j + 1).ToString()]);
}
// Printing resources still needed
Console.WriteLine();
foreach (SysProcess p in processes.Values)
{
p.print_needed();
}
//a) Find a row in the Need matrix which is less than the Available vector.
//If such a row exists, then the process represented by that row may complete
//with those additional resources. If no such row exists, eventual deadlock is possible.
Dictionary<String, int> _currentavailsum;
foreach (SysProcess p in processes.Values)
{
int TotalSproccounter = 0;
String safelead;
if (isprocessSafe(n, p, availsum))
{
TotalSproccounter++;
safelead = p.id;
_currentavailsum = new Dictionary<String, int>();
_currentavailsum = availsum;//get a copy of the original data to begin with
foreach (SysProcess q in processes.Values)
{
if (q != p)//we only want to compare with the others from here
{
if (isprocessSafe(n, p, _currentavailsum))
{
update_availsum(n, q, ref _currentavailsum);//update the currentavail count
TotalSproccounter++;
//update print
safelead += ", " + q.id;
}
}
}
if (TotalSproccounter == proc_num)
{
Console.WriteLine("Safe allocation < {0} >", safelead);
}
else
{
Console.WriteLine("Deadlock reached/unsafe allocation : < {0} >", safelead);
}
}
}
}
Console.ReadLine();
}
//compares the number of resources needed against the number of resources available
public static Boolean isprocessSafe(int n, SysProcess p, IDictionary<String, int> avail)
{
int safecount = 0;
foreach (String resourcekey in avail.Keys)
{
if (p.need_resources.ContainsKey(resourcekey) && p.need_resources[resourcekey] <= avail[resourcekey])
{
safecount++;
}
}
if (safecount == n)
{
return true;
}
return false;
}
//compares the number of resources needed against the number of resources available
public static void update_availsum(int n, SysProcess p, ref Dictionary<String, int> _currentavailsum)
{
foreach (String resourcekey in _currentavailsum.Keys)
{
if (p.need_resources.ContainsKey(resourcekey))
{
_currentavailsum[resourcekey] += p.need_resources[resourcekey];
}
}
}
}
//container class for processes
public class SysProcess
{
public String id { get; set; }
Dictionary<String, int> _max_resources = null; // will hold the Resource name and the the number of resources
Dictionary<String, int> _alloc_resources = null;//allocated resources
Dictionary<String, int> _need_resources = null;//allocated resources
public Dictionary<String, int> max_resources
{
get
{ return _max_resources; }
}
public Dictionary<String, int> alloc_resources
{
get
{
return _alloc_resources;
}
}
public Dictionary<String, int> need_resources
{
get
{
return _need_resources;
}
}
public SysProcess(String procID)
{
_max_resources = new Dictionary<String, int>();
_alloc_resources = new Dictionary<String, int>();
id = procID;
}
public void Add_max_resource(String resource, int count)
{
_max_resources.Add(resource, count);
}
public void add_alloc_resource(String resource, int count)
{
_alloc_resources.Add(resource, count);
_need_resources.Add(resource, _max_resources[resource] - alloc_resources[resource]);
}
public void print_needed()
{
Console.Write(id);
foreach (int s in _need_resources.Values)
{
Console.Write(" {0}", s);
}
}
}
在这里添加整个代码可能是一个好主意，因为我仍然无法解决这个问题。请帮忙
答案 0 :(得分：6)
问题在于使用有问题的方法Console.Read()。此方法将阻塞，直到输入完整的文本行，但它只返回第一个字符，剩下的文本留在输入缓冲区中。当执行Console.ReadLine()操作时，用于输入第一个值并取消阻止读取操作的回车符仍然位于输入缓冲区中。因此，返回一个空行。
我建议您将Console.Read().ToString()替换为Console.ReadLine()以解决此问题。
使用此代码可以证明问题：
static void Main(string[] args)
{
string value = Console.Read().ToString();
Console.WriteLine("You entered: {0}", value);
Console.WriteLine("Press ENTER to continue...");
Console.ReadLine(); // Returns immediately.
Console.WriteLine("Continuing....");
}
并修改如下：
string value = Console.ReadLine();
答案 1 :(得分：2)
您的项目是否配置为控制台应用程序？它需要使用不同的开关构建，以便在exe文件中设置标志，以便OS加载程序知道它需要为进程创建一个控制台窗口。 GUI应用程序不设置该标志，也不会获得控制台窗口。
在VS2010中，右键单击项目的“属性”链接，单击“应用程序”选项卡，然后将“输出类型”从“Windows应用程序”更改为“控制台应用程序”。重建并运行。
答案 2 :(得分：0)
您的输入中可能有重复/额外的换行符。这段代码看起来非常适合解析逗号分隔的文件......
答案 3 :(得分：0)
问题可能是您尝试从控制台读取的输入流中已有的内容。如果您不想担心缓冲区中已有的内容，可以尝试刷新它，以便从一个新的空输入状态开始。另外，所有Console.Read *函数似乎都是阻塞函数。但是，还有KeyAvailable属性，它指示是否有可用的内容。
这提供了以下代码：
private void clearInputBuffer()
{
while(Console.KeyAvailable)
{
Console.Read(); // read next key, but discard
}
}
或者，用于输入的缓冲区在基本级别是流。 TextReader，具体而言。这可以从
获得Console.In
所以你可以使用那里的函数，比如.ReadToEnd（），在你进入While（true）循环之前清除缓冲区。
答案 4 :(得分：0)
问题在于你误解了Console.Read的作用。它从输入流中读取下一个字符并将其作为整数返回。但是......这是好的部分，在你点击Enter之前什么都没有。因此，如果您在第一个提示符处输入“abc”并按Enter键，您将从缓冲区中获取第一个字符，作为整数（97）。但输入缓冲区将包含“bc”和换行符，然后由Readline使用。
如果您需要Console中的字符串，请拨打ReadLine，而不是Read。