Display a Variable in MessageBox c++
How to display a Variable in MessageBox c++ ?
string name = "stackoverflow"; MessageBox(hWnd, "name is: <string name here?>", "Msg title", MB_OK | MB_ICONQUESTION);
I want to show it in the following way (#1):
"name is: stackoverflow"
and this?
int id = '3'; MessageBox(hWnd, "id is: <int id here?>", "Msg title", MB_OK | MB_ICONQUESTION);
and I want to show it in the following way (#2):
id is: 3
how to do this with c++ ?
05 Answers
Create a temporary buffer to store your string in and use sprintf
, change the formatting depending on your variable type. For your first example the following should work:
char buff[100]; string name = "stackoverflow"; sprintf_s(buff, "name is:%s", name.c_str()); cout << buff;
Then call message box with buff as the string argument
MessageBox(hWnd, buff, "Msg title", MB_OK | MB_ICONQUESTION);
for an int change to:
int d = 3; sprintf_s(buff, "name is:%d",d);
3This can be done with a macro
#define MSGBOX(x) \ { \ std::ostringstream oss; \ oss << x; \ MessageBox(oss.str().c_str(), "Msg Title", MB_OK | MB_ICONQUESTION); \ }
To use
string x = "fred"; int d = 3; MSGBOX("In its simplest form"); MSGBOX("String x is " << x); MSGBOX("Number value is " << d);
Alternatively, you can use varargs (the old fashioned way: not the C++11 way which I haven't got the hang of yet)
void MsgBox(const char* str, ...) { va_list vl; va_start(vl, str); char buff[1024]; // May need to be bigger vsprintf(buff, str, vl); MessageBox(buff, "MsgTitle", MB_OK | MB_ICONQUESTION); } string x = "fred"; int d = 3; MsgBox("In its simplest form"); MsgBox("String x is %s", x.c_str()); MsgBox("Number value is %d", d);
This is the only one that worked for me:
std::string myString = "x = "; int width = 1024; myString += std::to_string(width); LPWSTR ws = new wchar_t[myString.size() + 1]; copy(myString.begin(), myString.end(), ws); ws[myString.size()] = 0; // zero at the end MessageBox(NULL, ws, L"Windows Tutorial", MB_ICONEXCLAMATION | MB_OK);
It's not good to see people still messing with buffers. That was unnecessary in 1998, and definitely today.
std::string name = "stackoverflow"; MessageBox(hWnd, ("name is: "+name).c_str(), "Msg title", MB_OK | MB_ICONQUESTION);
If you're using Unicode (which makes sense in the 21st century)
std::wstring name = L"stackoverflow"; MessageBox(hWnd, (L"name is: "+name).c_str(), L"Msg title", MB_OK | MB_ICONQUESTION);
Answer to your question:
string name = 'stackoverflow';
MessageBox("name is: "+name , "Msg title", MB_OK | MB_ICONQUESTION);
do in same way for others.
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