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Questions tagged [cout]

std::cout is the global stream object provided by the C++ standard library for writing to the standard output stream.

For more general questions about std::ostream use the or tags.

Bjarne Stroustrup, the creator of C++, explains that cout is pronounced "see-out" and the "c" stands for "character". (wcout is used for wide character output to the standard output stream)

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How to determine the size of an array of strings in C++?

I'm trying to simply print out the values contained in an array. I have an array of strings called 'result'. I don't know exactly how big it is because it was automatically generated. From what I've read, you can determine the size of an array by…
Jake Wilson
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How can I print a string to the console at specific coordinates in C++?

I'm trying to print characters in the console at specified coordinates. Up to now I have been using the very ugly printf("\033[%d;%dH%s\n", 2, 2, "str"); But I just had to ask whether C++ had any other way of doing this. The problem is not even that…
Shawn
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Order of execution in operator <<

I have difficulties in understanding the sequence of calls in the code below. I was expecting to see the output below A1B2 While I can see that the output I get is BA12 I thought that the call std::cout<< b->fooA() << b->fooB() <<…
Abruzzo Forte e Gentile
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what is the best way to avoid negative zero in output?

As in this question is said, there is some differences between negative and positive zero in floating point numbers. I know it's because of some important reasons. what I want to know is a short code to avoid negative zero in output. for example in…
Ali
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Why does overloading operator<< to print Eigen class member result in a segfault?

For the following struct struct TestClass { TestClass() : mat(Eigen::Matrix3i::Zero()) {} Eigen::Matrix3i mat; }; I would like to have an overloaded operator<< to print the mat member to std::cout. I tried std::ostream& operator<<(std::ostream&…
red
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Why is this lambda streamable?

To my surprise the following code prints 1. std::cout << [](const char* arg){ return arg[0]=='s'; } << std::endl; Can someone explain this, please?
SU3
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Check if ostream object is cout or ofstream, c++

Is there a way in C++ to check if an ostream object is cout or a ofstream object? Something like: ostream& output(ostream& out) { if (out == cout) return out; else { out << "something different because its not going to…
Jordan
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"cout" and "char address"

char p; cout << &p; This does not print the address of character p. It prints some characters. Why? char p; char *q; q = &p; cout << q; Even this does not. Why?
GandalfDGrey
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How to set a fixed width with cout?

I want to cout a table like output using c++. It should look like this Passes in Stock : Student Adult ------------------------------- Spadina 100 200 Bathurst 200 300 Keele 100 100 Bay …
Andrew Kim
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Limit the precision on std::cout of default values in boost::options_description

When I construct a boost::options_description instance like options.add_options() ("double_val", value(&config.my_double)->default_value(0.2), "it's a double"); and later want to have the automated output of the options that are available for my…
Christian
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C++ Unicode characters printing

I need to print some Unicode characters on the Linux terminal using iostream. Strange things happen though. When I write: cout << "\u2780"; I get: ➀, which is almost exactly what I want. However, if I write: cout << '\u2780'; I get: 14851712. The…
Sventimir
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iostream thread safety, must cout and cerr be locked separately?

I understand that to avoid output intermixing access to cout and cerr by multiple threads must be synchronized. In a program that uses both cout and cerr, is it sufficient to lock them separately? or is it still unsafe to write to cout and cerr…
zaphoyd
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Does std::cout have a return value?

I am curious if std::cout has a return value, because when I do this: cout << cout << ""; some hexa code is printed. What's the meaning of this printed value?
user1448323
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Where is cout declared?

My computer science professor wants us to find the declaration of cout. I've compiled a simple Hello world program using g++ and the -E parameter. Here's what my hello.cpp looks like: #include using namespace std; int main(){ string…
Moshe
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Thread safe cout technique. Am I missing something?

I'm working with some multithreaded code for a game project, and got a bit tired of sorting through the stdout vomit created by two threads using cout for debuging messages at the same time. I did some research and stared at a wall for an hour or…
Chris
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