Error Identifier Ostream Is Undefined
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Identifier Ofstream Is Undefined
more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us identifier endl is undefined Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like cout is undefined you, helping each other. Join them; it only takes a minute: Sign up identifier “ostream” is undefined error [closed] up vote 5 down vote favorite 1 i need to implement a number class that support operator << for output. i have an error: "identifier "ostream" is undefined" from some reason eventhough i included and try also here
Cout Was Not Declared In This Scope
the header file: Number.h #ifndef NUMBER_H #define NUMBER_H #include class Number{ public: //an output method (for all type inheritance from number): virtual void show()=0; //an output operator: friend ostream& operator << (ostream &os, const Number &f); }; #endif why the compiler isnt recognize ostream in the friend function? c++ compiler-errors operators ostream share|improve this question asked May 14 '13 at 11:07 Aviad Chmelnik 109314 closed as too localized by Peter Wood, Nicholas Wilson, Luca Geretti, nalply, Danack May 14 '13 at 12:40 This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question. Because as with all standard library types and functions, there just is no ostr
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up The #include exists, but I get an error: identifier “cout” is undefined. Why? up vote http://stackoverflow.com/questions/16541597/identifier-ostream-is-undefined-error 9 down vote favorite I learn C++ and COM through the books. In the IDE MS Visual Studio 2012 I have created new empty C++ project, and added some existing files to it. My CPP file contains #include row, but in editor I got such messages: Error: identifier "cout" is undefined end Error: identifier "endl" is undefined Screen: Why it happens? c++ visual-studio com visual-studio-2012 share|improve this question asked Nov 3 http://stackoverflow.com/questions/13208547/the-includeiostream-exists-but-i-get-an-error-identifier-cout-is-undefine '12 at 11:03 Andrey Bushman 2,79621654 1 try std::cout and std::endl –srbhkmr Nov 3 '12 at 11:04 1 try copy paste for code –sehe Nov 3 '12 at 11:07 2 Fresh and uncorrupted mind that doesn't know about 'using namespace std;'. Sweet :) –jrok Nov 3 '12 at 11:09 add a comment| 3 Answers 3 active oldest votes up vote 21 down vote accepted You need to specify the std:: namespace: std::cout << .... << std::endl;; Alternatively, you can use a using directive: using std::cout; using std::endl; cout << .... << endl; I should add that you should avoid these using directives in headers, since code including these will also have the symbols brought into the global namespace. Restrict using directives to small scopes, for example #include inline void foo() { using std::cout; using std::endl; cout << "Hello world" << endl; } Here, the using directive only applies to the scope of foo(). share|improve this answer edited Nov 3 '12 at 11:13 answered Nov 3 '12 at 11:04 juanchopanza 163k15215335 Thank you! I forgot about it. :) Now all is OK. –Andrey Bushman Nov 3 '12 at 11:16 add a comment| up vote 3 down vote cout is in std namespace, you shall us
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the http://stackoverflow.com/questions/7569226/defining-an-output-file-stream-within-a-class workings and policies of this site About Us Learn more about Stack http://www.cplusplus.com/forum/beginner/67511/ Overflow the company Business Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; is undefined it only takes a minute: Sign up Defining an output file stream within a class up vote 0 down vote favorite How can I define an output file stream within a class, so that I don't have to keep passing it around to functions. Basically what I want to do is this: class A { private: ofstream otp ; error identifier ostream }; Then in my constructor, I simply have otp.open("myfile"); and in other functions I have otp.open("myfile", ios::app); , but it fails during compile time, saying: ../thermo.h(18): error: identifier "ofstream" is undefined ofstream otp ; I have made sure to #include Thanks! c++ class fstream share|improve this question asked Sep 27 '11 at 12:37 Amit 2,216103759 I guess it's not such a big deal to keep redefining ofstream in each of my functions`... Was just wondering if what I'm trying to do is possible, probably for curiosity sake –Amit Sep 27 '11 at 12:38 add a comment| 2 Answers 2 active oldest votes up vote 3 down vote accepted You'll need to use the fully qualified name, std::ofstream. share|improve this answer answered Sep 27 '11 at 12:40 Mike Seymour 189k12255454 Worked! Excellent. thank you. Would you mind giving a small explanation why I needed to do that even when I use namespace std ? –Amit Sep 27 '11 at 12:41 @Amit: if you put using namespace std in a module af
#include #include #include void get_file(char in_file, char out_file, ifstream fin, ofstream fout); /* to get, open, and test the files for input and output data.*/ using namespace std; int main(int argc, char *argv[]) { char in_file[40], out_file[40]; ifstream fin; ofstream fout; get_file (in_file, out_file, fin, fout); system("PAUSE"); return EXIT_SUCCESS; } void get_file (char in_file, char out_file, ifstream fin, ofstream fout) { cout << "What is the name of the file containing data to be analyzed?" cin >> in_file; fin.open(in_file); if (fin.fail()) { cout << "Input file failed.\n."; exit(1); } cout << "What is the name of the file where you would like to store data? \n" cin >> out_file; fout.open(out_file); if (fout.fail()) { cout << "imput file failed.\n."; exit(1); } Apr 5, 2012 at 7:12pm UTC Moschops (7069) You're trying to use objects that live in the std namespace before you've sorted out the namespaces. Apr 5, 2012 at 7:27pm UTC blackcoder41 (1426) 1
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#include #include #include #include // this goes first before referencing classes, objects and functions inside the namespace using namespace std; // you forgot char* // also pass ifstream and ofstream by reference or by pointer // why?? because its copy constructor is private (can't be copied) void get_file(char* in_file, char* out_file, ifstream& fin, ofstream& fout); /* to get, open, and test the files for input and output data.*/ int main(int argc, char *argv[]) { char i