Humans are also regularly harmed by pollution. Long-term exposure to air pollution, for example, can lead to chronic respiratory disease, lung cancer and other diseases. Toxic chemicals that accumulate in top predators can make some species unsafe to eat.
#include <iostream> is the Standard C++ way to include header files, the. 'iostream' is an identifier that maps to the file iostream.h. In older C++ you had to specify the filename of the header file, hence #include. <iostream.h>. Older compilers may not recognise the modern method, newer.
You can define it in simple words as the flow of data which can be the input flow and output flow. So you can think of it as the flow of data from a program to a file or vice versa. The below image may help you understand it better: From MSDN. The stream is the central concept of the iostream classes.