In C++ std::ostream is the base class for output streams.
Questions tagged [ostream]
765 questions
280
votes
6 answers
How to properly overload the << operator for an ostream?
I am writing a small matrix library in C++ for matrix operations. However my compiler complains, where before it did not. This code was left on a shelf for 6 months and in between I upgraded my computer from debian etch to lenny (g++ (Debian…
Matthias van der Vlies
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- 3
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105
votes
9 answers
How to make C++ cout not use scientific notation
double x = 1500;
for(int k = 0; k<10 ; k++){
double t = 0;
for(int i=0; i<12; i++){
t += x * 0.0675;
x += x * 0.0675;
}
cout<<"Bas ana: "<
Yunus Eren Güzel
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85
votes
17 answers
how do I print an unsigned char as hex in c++ using ostream?
I want to work with unsigned 8-bit variables in C++. Either unsigned char or uint8_t do the trick as far as the arithmetic is concerned (which is expected, since AFAIK uint8_t is just an alias for unsigned char, or so the debugger presents it.
The…
Nathan Fellman
- 122,701
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84
votes
5 answers
overloading friend operator<< for template class
I have read couple of the questions regarding my problem on StackOverflow.com now, and none of it seems to solve my problem. Or I maybe have done it wrong...
The overloaded << works if I make it into an inline function. But how do I make it work in…
starcorn
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70
votes
9 answers
Is there a null std::ostream implementation in C++ or libraries?
I'm looking for a std::ostream implementation that acts like /dev/null. It would just ignore anything that is streamed to it. Does such a thing exist in the standard libraries or Boost? Or do I have to roll my own?
paperjam
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59
votes
9 answers
How to use C++ std::ostream with printf-like formatting?
I am learning C++. cout is an instance of std::ostream class.
How can I print a formatted string with it?
I can still use printf, but I want to learn a proper C++ method which can take advantage of all C++ benefits. I think this should be possible…
eonil
- 83,476
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54
votes
8 answers
Floating point format for std::ostream
How do I do the following with std::cout?
double my_double = 42.0;
char str[12];
printf_s("%11.6lf", my_double); // Prints " 42.000000"
I am just about ready to give up and use sprintf_s.
More generally, where can I find a reference on std::ostream…
Jive Dadson
- 16,680
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- 65
46
votes
6 answers
How to inherit from std::ostream?
I've been googling around and I just can't find a simple answer to this. And it should be simple, as the STL generally is.
I want to define MyOStream which inherits publicly from std::ostream. Let's say I want to call foo() each time something is…
Michael
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- 18
46
votes
5 answers
Why is istream/ostream slow
At 50:40 of http://channel9.msdn.com/Events/GoingNative/2013/Writing-Quick-Code-in-Cpp-Quickly Andrei Alexandrescu makes a joke about how not efficient/slow istream is.
I had an issue in the past with ostream being slow and fwrite being…
user34537
38
votes
2 answers
Why is operator<< function between std::ostream and char a non-member function?
When I ran the following program
#include
int main()
{
char c = 'a';
std::cout << c << std::endl;
std::cout.operator<<(c) << std::endl;
return 0;
}
I got the output
a
97
Digging further at…
R Sahu
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25
votes
3 answers
How do I create my own ostream/streambuf?
For educational purposes I want to create a ostream and stream buffer to do:
fix endians when doing << myVar;
store in a deque container instead of using std:cout or writing to a file
log extra data, such as how many times I did <<, how many…
user34537
24
votes
3 answers
How do the stream manipulators work?
It is well known that the user can define stream manipulators like this:
ostream& tab(ostream & output)
{
return output<< '\t';
}
And this can be used in main() like this:
cout<<'a'<
Narek
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24
votes
6 answers
Center text in fixed-width field with stream manipulators in C++
I am refactoring some legacy code which is using printf with longs strings (without any actual formatting) to print out plain text table headers which looks notionally like this:
| Table | Column | Header |
which are currently being produced…
Keith Pinson
- 7,835
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21
votes
3 answers
Platform independent /dev/null in c++
Possible Duplicate:
Implementing a no-op std::ostream
Is there any stream equivalent of NULL in c++? I want to write a function that takes in a stream if the user wants to have the internal outputted to somewhere, but if not, the output goes into…
calccrypto
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20
votes
3 answers
Does Overloading Operator<< works inside the class?
I mean, I was trying to overload the operator<< inside the class
like this
class A {
public:
ostream &operator<<(ostream &os);// which doesnt work
private:
friend ostream &operator<<(ostream &os, const A& a);…
howtechstuffworks
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