WRITING CONSOLE APPLICATIONS IN C

Transcription

1 WRITING CONSOLE APPLICATIONS IN C with Visual Studio 2017 A brief step-by-step primer for ME30 Bryan Burlingame, San José State University

2 The Visual Studio 2017 Community Edition is a free integrated development environment (IDE) for Windows. An IDE integrates a text editor, compiler, debugger and other tools in one package to support the software development process. We will be using this environment to craft C programs for ME30. This tutorial illustrates how to successfully compile a simple C console program in the Visual Studio environment. If installed with Visual C++ support (as it is in our labs), the Visual Studio environment is a fine tool for the generation of programs written in the C language. By definition, C++ is a superset of C. To support this feature of the C++ language, Visual C++ provides full support for the C99 version of the C language. A console exists within all three major PC operating systems (Windows, Linux, and MacOS). The console provides a command line interface (CLI) to a computer and is a very common tool within engineering. By being completely text based, command line tools can be structured for easy automation and frequently provide more efficient operation than graphical user interfaces (GUIs). Using the Windows console is outside the scope of this tutorial and having deep knowledge of any CLI is not required for this course. Writing a console application in C using Visual Studio 1. Launch Visual Studio 2017 Community Edition 2. Choose File -> New -> Project... 1 P age

3 Choose Visual Studio C++, Win32 Template 3. Windows Desktop Wizard 4. Provide a name for the project Project_name_goes_here in this case. (Note the location) 5. Click OK 2 P age

4 Choose Empty Project, deselect all other options 7. Click OK 8. An empty project opens 3 P age

5 9. Add a source file by Right Clicking on Source Files to pull up the context menu 10. Select Add -> New Item 4 P age

6 Choose Visual C Choose C++ File (cpp) (note: C++ is a super-set of C. We are taking advantage of this to write our applications in C.) 13. Name the file with a.c file extension, C_file_name.c in this case 14. Click Add 5 P age

7 The file is now open in the edit window. Notice the filename entered in step 13 is on the tab. 16. Notice the C file we created has been added to the Solution Explorer as a source file 17. Type in your program. A simple Hello World program has been entered as an example. 6 P age

8 18. To compile your program, Choose Build -> Build Project Name (the name use in step 4). Project_name_goes_here in this example 19. The results of the compilation attempt are displayed in the Output panel. This example demonstrates a Syntax Error. The parser will attempt to direct you to the nature of the error and the line where the error occurs. 7 P age

9 20. This example demonstrates the Output of a successful compilation. Even on successful compilation, the programmer should read the output results to check for any warnings. Warnings are areas of concern in the code which the parser or compiler has found. These warnings should be fixed. 21. To run the program, choose Debug -> Start Debugging or Debug -> Start Without Debugging (debugging will be discussed later in the semester) 8 P age

10 23. For console applications, Visual Studio will spawn a console window. The program will run within this window. Once the program ends, a prompt Press any key to continue... will be displayed. Pressing a key will make the console window close. 24. The executable for the console application will reside in the Debug subdirectory of the project directory created in step 4 9 P age

11 Resolving _CRT_SECURE_NO_WARNINGS error For modern systems running complex programs, some of the input functions in the C standard libraries (scanf, for example) may create unexpected runtime errors. To attempt to protect the programmer, Visual Studio warns the programmer about this condition if it sees use of one of these functions. For the purposes of this course, we can safely suppress these warnings. 1. The error identifies the problematic function and suggest an alternate. Visual Studio 2017 will refuse to compile this code until the warning is resolved. 10 P age

12 2. The solution is to add the line #define _CRT_SECURE_NO_WARNINGS before the libraries are included. This preprocessor directive instructs the C compiler to ignore these specific warnings, allowing the program to compile. 11 P age