kommatal

Du kunne prøve noget lignende dette:

<pre>
#include <iostream>

float SaetAntalDecimaler(float p_Tal,unsigned int p_Decimaler)
{
unsigned int TempTal = 1;

for( unsigned int Indeks = 0;Indeks < p_Decimaler;++Indeks)
TempTal *= 10;

p_Tal *= TempTal;

//Rund af
unsigned int TempTal2 = p_Tal+0.5F;

return (static_cast<float>(TempTal2)/TempTal);

}

int main()
{
const float TalMedMangeDecimaler = 5.142455325355532;
//Variablen har over 5 decimaler.
float KommaTalMed5Decimaler = SaetAntalDecimaler(TalMedMangeDecimaler,5);
//Variablen har nu over 5 decimaler
std::cout << KommaTalMed5Decimaler << std::endl;

std::cin.get();

return 0;
}
</pre>


[Redigeret d. 22/07-05 22:53:03 af Ebnuv]

Hvis man dividerer to heltal (integers) får man et heltal.

For at få det i kommatal (float/double) kan man:

int i = 5;
int j = 2;
double x = 1.0*i/5;

Man vil normalt regne med lige så mange cifre som compileren/processoren synes, og så vælge antal cifre når man udskriver.

F.ex:

#include <iostream>
#include <iomanip>

int main()
{
   int a = 50;
   int b = 3;
   double res = 1.0*a/b;
   std::cout << std::setprecision(5) << res << std::endl;
}

F.ex:

Kode 

#include <iostream>
#include <iomanip>

int main()
{
   int a = 50;
   int b = 3;
   double res = 1.0*a/b;
   std::cout << std::setprecision(5) << res << std::endl;
}

Hej

Jeg laver det som et windows program så hvordan gør jeg så ?

Du kan bruge en std::stringstream i stedet for cout.

En stringstream virker på samme måde som cout, men gemme i en streng.

Du kan få fat i denne streng i form af en std::string ved at bruge stream'ens str() function.

Du kan bruge en std::stringstream i stedet for cout.

En stringstream virker på samme måde som cout, men gemme i en streng.

Du kan få fat i denne streng i form af en std::string ved at bruge stream'ens str() function.

Kan jeg få et ekempel ?

Et meget hurtigt eksempel:

#include <windows.h>
#include <commctrl.h>
#include <sstream>
#include <string>
#include <iomanip>

enum WindowsId
{
   FirstEditId = 256,
   ButtonId,
};

HINSTANCE InstanceHandle;
int NumPush = 0;

LRESULT CALLBACK DialogProc(HWND hwndDlg, UINT msg, WPARAM wParam, LPARAM lParam)
{
   switch(msg)
   {
   case WM_CREATE:
      CreateWindowEx(WS_EX_CLIENTEDGE,
                     "EDIT",
                     "",
                     WS_CHILD | WS_VISIBLE | ES_NUMBER | WS_TABSTOP | WS_GROUP,
                     5, 5, 380, 20,
                     hwndDlg,
                     (HMENU)(FirstEditId),
                     InstanceHandle,
                     0);

      CreateWindow("BUTTON",
                   "Push Me",
                   WS_CHILD | WS_VISIBLE | WS_TABSTOP,
                   10, 105, 75, 25,
                   hwndDlg,
                   (HMENU )ButtonId,
                   InstanceHandle,
                   0);
      break;
   case WM_COMMAND:
      if(HIWORD(wParam) == BN_CLICKED && LOWORD(wParam) == ButtonId)
      {
         std::stringstream SS;
         double d = 5.0/3.0;
         SS << "Lets play with numbers: ";
         SS << std::setprecision(5)  << d;
         std::string T = SS.str();
         SetDlgItemText(hwndDlg, FirstEditId, T.c_str());
      }
      break;
   }
   return DefWindowProc(hwndDlg, msg, wParam, lParam);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE, LPSTR lpCmdLine, INT nCmdShow)
{
   InstanceHandle = hInstance;
   InitCommonControls();
   WNDCLASS wc;
   memset(&wc, 0, sizeof(WNDCLASS));
   wc.style = CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS;
   wc.lpfnWndProc = DialogProc;
   wc.hInstance = InstanceHandle;
   wc.hbrBackground = (HBRUSH )(COLOR_BTNFACE + 1);
   wc.lpszClassName = "WhateverClass";
   wc.hCursor = LoadCursor(NULL, IDC_ARROW);
   if(!RegisterClass(&wc))
      return FALSE;

   HWND WindowHandle = CreateWindow("WhateverClass",
                                    "Calc", // Caption text
                                    WS_MINIMIZEBOX | WS_VISIBLE | WS_MAXIMIZEBOX |
                                    WS_CAPTION | WS_BORDER | WS_SYSMENU,
                                    100, 100, 400, 240,  // Position
                                    NULL,
                                    NULL,
                                    InstanceHandle,
                                    0);
   MSG Msg;
   while(GetMessage(&Msg, WindowHandle, 0, 0xFFFF) > 0)
   {
      if(!IsDialogMessage(WindowHandle, &Msg))
      {
         TranslateMessage(&Msg);
         DispatchMessage(&Msg);
      }
   }
   return 0;
}

Et meget hurtigt eksempel:

Kode 

#include <windows.h>
#include <commctrl.h>
#include <sstream>
#include <string>
#include <iomanip>

enum WindowsId
{
   FirstEditId = 256,
   ButtonId,
};

HINSTANCE InstanceHandle;
int NumPush = 0;

LRESULT CALLBACK DialogProc(HWND hwndDlg, UINT msg, WPARAM wParam, LPARAM lParam)
{
   switch(msg)
   {
   case WM_CREATE:
      CreateWindowEx(WS_EX_CLIENTEDGE,
                     "EDIT",
                     "",
                     WS_CHILD | WS_VISIBLE | ES_NUMBER | WS_TABSTOP | WS_GROUP,
                     5, 5, 380, 20,
                     hwndDlg,
                     (HMENU)(FirstEditId),
                     InstanceHandle,
                     0);

      CreateWindow("BUTTON",
                   "Push Me",
                   WS_CHILD | WS_VISIBLE | WS_TABSTOP,
                   10, 105, 75, 25,
                   hwndDlg,
                   (HMENU )ButtonId,
                   InstanceHandle,
                   0);
      break;
   case WM_COMMAND:
      if(HIWORD(wParam) == BN_CLICKED && LOWORD(wParam) == ButtonId)
      {
         std::stringstream SS;
         double d = 5.0/3.0;
         SS << "Lets play with numbers: ";
         SS << std::setprecision(5)  << d;
         std::string T = SS.str();
         SetDlgItemText(hwndDlg, FirstEditId, T.c_str());
      }
      break;
   }
   return DefWindowProc(hwndDlg, msg, wParam, lParam);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE, LPSTR lpCmdLine, INT nCmdShow)
{
   InstanceHandle = hInstance;
   InitCommonControls();
   WNDCLASS wc;
   memset(&wc, 0, sizeof(WNDCLASS));
   wc.style = CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS;
   wc.lpfnWndProc = DialogProc;
   wc.hInstance = InstanceHandle;
   wc.hbrBackground = (HBRUSH )(COLOR_BTNFACE + 1);
   wc.lpszClassName = "WhateverClass";
   wc.hCursor = LoadCursor(NULL, IDC_ARROW);
   if(!RegisterClass(&wc))
      return FALSE;

   HWND WindowHandle = CreateWindow("WhateverClass",
                                    "Calc", // Caption text
                                    WS_MINIMIZEBOX | WS_VISIBLE | WS_MAXIMIZEBOX |
                                    WS_CAPTION | WS_BORDER | WS_SYSMENU,
                                    100, 100, 400, 240,  // Position
                                    NULL,
                                    NULL,
                                    InstanceHandle,
                                    0);
   MSG Msg;
   while(GetMessage(&Msg, WindowHandle, 0, 0xFFFF) > 0)
   {
      if(!IsDialogMessage(WindowHandle, &Msg))
      {
         TranslateMessage(&Msg);
         DispatchMessage(&Msg);
      }
   }
   return 0;
}

Jeg er ked af at sige det men jeg kan ikke få det til at virke. Findes der ikke en lettere måde at få et kommatal med 5 decimaler på ?

Mvh.

Søren

Hej

jeg fandt selv ud af det på en anden måde ved

sprintf(boe, "%f\\n",res2);

Men tak for at i gad at svare allesammen, så i får lige nogle UP