First quick application covering why you may get iostream, cin and cout errors. Programming code provided below: Copy the following codes into the header file: - stdafx.h: // stdafx.h : include file for standard system include files, // or project specific include files that are used frequently, but // are changed infrequently // #pragma once #include #include using namespace std; // TODO: reference additional headers your program requires here Copy the main code for the main file: 3_test.cpp But you can name your file anything. Below is the rest of the programming codes: // 3_test.cpp : Defines the entry point for the console application. // #include "stdafx.h" //Percentage marks attained by a student in three exams //are to be entered to a computer. An indication of Pass //or Fail is given out after the three marks are entered. //The criteria for passing are as follows: //A student passes if all three examinations are passed. //Addition...