How to write a countdown program in C + +

Question

hi all How to write a countdown program. such as: #include using namespace std; int main() { int s; int SetSecondTime(int); s=SetSecondTime(60); if(s>0) cout else exit(0); return 0; } int SetSecondTime(int second) { for(;second;second--) return second; } However the above code and countdown function cannot be achieved. thanks.

Vulpes · Answer

'\b' only moves the cursor back a space - it doesn't delete the character at the new cursor position like pressing the Backspace key does. To delete the character you therefore have to print a space. It probably looks the same to you because when you move the cursor back the next thing to be printed will overprint the 0 anyway. You can see better what happens if you insert a delay between the operations: cout Sleep(3000); cout Sleep(3000); // print something else

Sam Hobbs · Answer

In my opinion I think someone should have gotten clarification about what you needed. That way we could have chosen the best solution for you. I could explain my code; that is not a problem. So please tell me this. Does your program not need to do anything while it does the countdown? If so then Sleep will work. Do you have no need to do any other formatting in terms of putting text at specified places in the screen? Let my sample code be a sample for Vulpes. It shows Vulpes that there are often alternatives and if we want to provide the best possible answer for members it helps to get clarification of the requirements first. My suggestion shows how to do a countdown asynchronously and it shows how to use more complex formatting in a Windows API console program.

Ken H · Answer

hi Sam Hobbs  I can not understand your code.In addition my problem has been solved. thank for you.

Sam Hobbs · Answer

As I indicated I do not know why you need to do this. I would not have tried to help if I knew my suggestion would not be useful. Can you please take a few seconds to explain what you need to do that makes my suggestion not relevant?

Ken H · Answer

I understand how it works. It not delete character only move the cursor and point it waiting to user continue to input as stead it. Cursor is stuck at 0 and the system to output the Press any key to continue Therefore the Press any key to continue stead 0 by. cout Sleep(3000); cout Sleep(3000); thank for you Vulpes.

Sam Hobbs · Answer

You do not explain why you need to do this. If you need to do anything during the countdown then Sleep is a problem. You have not said that you do but the following code shows use of a waitable timer. A waitable timer could be used so that your program can do other things during the countdown. The following program also shows use of the Console I/O functions that provide extensive formatting features. Note that you should not try mixing std::wcout (or std::cout) and std::wcin (or std::cin) with console I/O. I did in this sample but you cannot rely on it to be formatted properly if you do. The following program also uses Unicode but I assume you can convert it to non-Unicode. #include stdafx.h void WriteString(HANDLE hStdout std::wstring String) { const _TCHAR *pBuffer = String.c_str(); DWORD NumberOfCharsWritten; WriteConsole(hStdout pBuffer _tcsclen(pBuffer) &NumberOfCharsWritten NULL); } DWORD Wait(DWORD MilliSeconds) { DWORD dw; HANDLE hTimer; LARGE_INTEGER DueTime; LONGLONG MilliSecond=-10000; DueTime.QuadPart = MilliSeconds * MilliSecond; hTimer = CreateWaitableTimer(NULL TRUE NULL); if (!SetWaitableTimer(hTimer &DueTime 0 NULL NULL FALSE)) { CloseHandle(hTimer); return WAIT_FAILED; } dw = WaitForSingleObject(hTimer 10000); // A maximum of 10 seconds CloseHandle(hTimer); return dw; } int _tmain( int argc _TCHAR* argv[]) { CONSOLE_SCREEN_BUFFER_INFO csbiInfo; std::wstring Message; HANDLE hStdout = GetStdHandle(STD_OUTPUT_HANDLE); GetConsoleScreenBufferInfo(hStdout &csbiInfo); SetConsoleTextAttribute(hStdout FOREGROUND_GREEN); for ( int i=9; i>0; --i) { SetConsoleCursorPosition(hStdout csbiInfo.dwCursorPosition); std::wstringstream ss; ss Countdown:  ) WriteString(hStdout ss.str()); Wait(1000); } SetConsoleTextAttribute(hStdout csbiInfo.wAttributes); std::wcout \nDone\n ); return 0; } Oh and the headers are: #include #include #include #include #include #include

Ken H · Answer

#include #include using namespace std; void main() { /* cout cout \b  ; //output result is:9 */ cout cout \b ; //Output is also:9 } I get confused by the above code the. cout \b  ; //why want input a space? cout \b ;//This not can.why?

Vulpes · Answer

cout moves the cursor back a space and then prints a space thereby deleting the last character entered. cout moves the cursor to the start of the line ('carriage return' on a typewriter) so that the next time text is printed it will over-print what's already there.

Ken H · Answer

The principle of the following code to run: if (s % 10 == 9)cout cout thanks

Vulpes · Answer

Did you remember to incorporate this line? if (s % 10 == 9) cout When the countdown reaches a number ending in 9 this line removes the last character printed which will be a zero and should therefore deal with the problem you mentioned.

Ken H · Answer

If the number is greater than 10 to be wrong such as:input is 10 90 80 ....

Ken H · Answer

very perfect. thank very much.

Vulpes · Answer

Just change the while loop to this: while(s >= 0) { cout s = SetSecondTime(s); Sleep(1000); if (s % 10 == 9) cout cout }

Ken H · Answer

I just want to let the countdown is displayed in the same location do not want to refresh screen. I do not want running results of the following: Please enter the number of seconds for the countdown: 5 countdown is:5 countdown is:4 countdown is:3 countdown is:2 countdown is:1 countdown is:0 Press any key to continue I only wish to display a string. such as: Please enter the number of seconds for the countdown: 5 countdown is:5// on a single line display Press any key to continue thank.

Ken H · Answer

Great this is what I want. thank you for Vulpes.

Vulpes · Answer

To make the countdown dynamic just make the highlighted changes: #include #include windows.h using namespace std; int main() { int s; int SetSecondTime(int); cout cin >> s; cout while(s >= 0) { cout s = SetSecondTime(s); Sleep(1000); } return 0; } int SetSecondTime(int second) { for(; --second ;) return second; }

Ken H · Answer

hi vulpes I like the stopwatch as dynamic countdown. thanks.

Vulpes · Answer

If you have to do it by repeatedly calling another function then this should work: using namespace std; int main() { int s; int SetSecondTime(int); s = 60; while(s >= 0) { cout s = SetSecondTime(s); } return 0; } int SetSecondTime(int second) { for(; --second ;) return second; }