The standard library
<iostream> defines few streams for input and output:
|stream | description | |-------|----------------------------------| |cin | standard input stream | |cout | standard output stream | |cerr | standard error (output) stream | |clog | standard logging (output) stream |
Out of four streams mentioned above
cin is basically used for user input and other three are used for outputting the data. In general or in most coding environments
cin (console input or standard input) is keyboard and
cout (console output or standard output) is monitor.
cin >> value cin - input stream '>>' - extraction operator value - variable (destination)
cin here extracts the input entered by the user and feeds in variable value. The value is extracted only after user presses ENTER key.
cout << "Enter a value: " cout - output stream '<<' - insertion operator "Enter a value: " - string to be displayed
cout here takes the string to be displayed and inserts it to standard output or monitor
All four streams are located in standard namespace
std so we need to print
std::stream for stream
stream to use it.
There is also a manipulator
std::endl in code. It can be used only with output streams. It inserts end of line
'\n' character in the stream and flushes it. It causes immediately producing output.