2016年4月28日 · char c; cin >> c; cout << c; cin >> c; cout << c; and wrote to the console ab, the pressed enter. So I got ab at the next line. But I can't understand how it works. Before pressing enter the program doesn't read anything, right? After pressing, it reads a, save it to char c, then reads char c, writes a to the console. It's OK.

so cout << "hello" means output to screen when cin >> a means asks from a user input for variable a. cout can also use "+" like for example you can add more strings to one stream like this. cout << "Hello" << "world" << "I am john"; cin in the same way can …

2011年7月22日 · std::cin is an object of class istream and represents the standard input stream (i.e. the keyboard) which corresponds to stdin in C stream. cin >> x would firstly read an int from the standard input stream and assignment it to x. After that return a self reference to cin. So the return value of function call cin >> x is still cin.

2012年5月19日 · std::cout << 5; // writes the integer 5 to the standard output int x; std::cin >> x; // reads an integer from the standard input It is overloaded for all the standard types. And most people override them for their own user defined types.

The statements cin and cout in general use seem to be slower than scanf and printf in C++, but actually they are FASTER! The thing is: In C++, whenever you use cin and cout, a synchronization process takes place by default that makes sure that if you use both scanf and cin in your program, then they both work in sync with each other. This sync ...

2012年4月14日 · The accepted answer shows the right way to redirect cin and cout. You need to construct another stream object whose life time exceeds that of cin or cout. If you want to write a function works like freopen, you can alloc an array for each stream to be redirected, to save the allocated stream objects.

2014年8月27日 · I was just programming in c++, when all of a sudden all the "cout"s and "cin"s were errors and "Ambiguous". Including System. I don't know why this happened. Everything was fine, I was coding the same program for about 2 hours, when it just... happened. EDIT

2017年10月5日 · cin and cout are global instance of istream and ostream classes. When you use operator<< / operator>> , they are return stream objects to provide chaining. When you write something like std::cout << "he" << 11 << 'o' , it's provide calling std::cout << "he" at first (in case of left associativity of operator<< ).

Программа по вычислениям полностью устраивает, она перемножает 2 матрицы указанного размера с рандомными числами, она запускается и правильно считает, но показывает, что есть ошибки типа: c...

2015年7月1日 · For a quick explanation: the first line turns off buffer synchronization between the cin stream and C-style stdio tools (like scanf or gets) — so cin works faster, but you can't use it simultaneously with stdio tools. The second line unties cin from cout — by default the cout buffer flushes each time when you read something from cin. And ...