Appendix M Introduction to Microsoft Visual C++.NET

Transcription

1 Appendix M Introduction to Microsoft Visual C++.NET This appendix serves as a quick reference for performing the following operations using the Microsoft Visual C++.NET integrated development environment (IDE): Starting a new project and entering code Saving a project to disk Compiling and executing a project Opening an existing project Creating multi-file projects Starting a New project The first step in creating a program with Visual C++.NET is to start a project. A project is a group of one or more files that make up a software application. (Even if your program consists of no more than a single source code file, it still must belong to a project.) To start a project: 1. Launch Microsoft.NET. The IDE window opens and allows for a number of options, which are shown in Figure M-1. Click the New Project button in the main window as shown in Figure M-1. (If you do not see the New Project button, click File on the menu bar, then click New, then click Project.) 1308

2 Introduction to Microsoft Visual C++.NET 1309 Menu bar Figure M-1 New Project Button 2. The New Projects dialog box appears, as shown in Figure M-2. Under Project Types (the left pane) select Visual C++ Projects. Under Templates (the right pane), scroll down to and select WIN 32 Project. Figure M-2

3 1310 Introduction to Microsoft Visual C++.NET 3. When you create a project, Visual C++.NET creates a folder where all the project files are normally stored. The folder is called the project folder and it has the same name as the project. The Location text box lets you type in or browse to a location on your system where the project folder will be created. If you do not want to keep the default location, click the Browse... button to select a different one. Once you have selected a folder the dialog box should appear similar to Figure K-3. Figure M-3 4. Enter the name of the project (such as Lab6, or Program5) in the Name text box. (Do not enter an extension for the filename.) Figure M-3 shows an example. Click the OK button if you are satisfied with the name and directory for the project. The Win32 Application Wizard starts and you should see the dialog box shown in Figure M-4. Application Settings option Figure M-4

4 Introduction to Microsoft Visual C++.NET Click the Application Settings options, which is shown in Figure M-4. The dialog box should now appear as shown in Figure M-5. Figure M-5 6. Click the Console Application button and click the Empty Project check box. The dialog box should now appear as shown in Figure M-6. Figure M-6 7. Click the Finish button to build the project. This will take you to the main screen with an empty project as shown in Figure M-7.

5 1312 Introduction to Microsoft Visual C++.NET Figure M-7 8. Now you should insert a new C++ source file into the project. Click Project on the menu bar and then choose Add New Item. You should see the Add New Item dialog box shown in Figure M-8. Click the C++ File icon in the templates pane. In the name box, enter the name of the source file. (This can be the same as the project name, if you wish.) Figure M-9 shows an example of the dialog box with this step completed. Figure M-8

6 Introduction to Microsoft Visual C++.NET 1313 Figure M-9 9. Click the Open button to create the C++ file. This creates an empty source file and adds it to the project. You should see something similar to Figure M-10. Note that above the text editor is a tab showing the name of the file that is currently open. To the right is a window showing the files that are in the project. This is called the Solution Explorer window. Figure M-11 shows the screen after a C++ program has been entered into the editor. Name of file currently open in the editor Solution Explorer window shows the files in this project Figure M-10

7 1314 Introduction to Microsoft Visual C++.NET Figure M-11 Saving Your Project to Disk It is important to periodically save your work. To do so, click File on the menu bar, then click Save All on the File menu. Compiling and Executing Once you have entered a program s source code, you may compile and execute it by any of the following methods: Click the Debug menu item and choosing Start without Debugging as shown in Figure M-12. by pressing Ctrl+F5

8 Introduction to Microsoft Visual C++.NET 1315 Figure M-12 After performing one of these steps, if you see the dialog box in Figure M-13, click the Yes button. Figure M-13 The Output window shown in Figure M-14 appears at the bottom of the screen. This window shows status messages as the program is compiled. Error messages are also displayed in this same area. Figure M-14 When compiling a program you will see the dialog box in Figure M-15 if the program has syntax errors. Click the No button. Next you will see one or more error messages displayed at the bottom of the screen, as shown in Figure M-16. Figure M-15

9 1316 Introduction to Microsoft Visual C++.NET Figure M-16 If you see an error message, double-click it and the editor will move the text cursor to the line of code where the error was encountered. For example, look at the program in Figure M-17. The first cout statement is missing a semi-colon. By double-clicking the error message, the text cursor is positioned on the line with the error. (Actually, in this case the cursor appears on the line after the statement with the missing semicolon. The compiler did not detect that the semicolon was missing until it encountered the beginning of the next line. Finding errors is not always straightforward.) Double-click this error message Figure M-17

10 Introduction to Microsoft Visual C++.NET 1317 If the program compiles successfully, an MS DOS window appears and the program runs. This is illustrated in Figure M-18. Figure M-18 Opening an Existing Project To open an existing project, click File on the menu bar, then click Open Solution. Use the resulting dialog box to browse to the folder containing your project. In that folder you should see a solution file. This file has the same name that you gave the project, and the.sln extension. Double-click this file to open the project. > Note: If the source file does not open in the editor, double-click the name of the file in the Solutions Explorer window. Creating a Multi-File Project Many of your programs consist of more than one file. For example, consider the following program, which is stored in the Appendix M folder on the student disk, under the name RectangleData.cpp: // This program uses the Rectangle class's specification // and implementation files. #include <iostream> #include "Rectangle.h" // Contains the class declaration. using namespace std; int main() { Rectangle box; float rectwidth, rectlength; // Define an instance of the class. // Local variable for width. // Local variable for length.

11 1318 Introduction to Microsoft Visual C++.NET } // Get the rectangle's width and length from the user. cout << "This program will calculate the area of a\n"; cout << "rectangle. What is the width? "; cin >> rectwidth; cout << "What is the length? "; cin >> rectlength; if (!box.setwidth(rectwidth)) // Store the width. cout << "Invalid value for width.\n"; else if (!box.setlength(rectlength)) // Store the length. cout << "Invalid value for length.\n"; else { // Display the rectangle's data. cout << "Here is the rectangle's data:\n"; cout << "Width: " << box.getwidth() << endl; cout << "Length: " << box.getlength() << endl; cout << "Area: " << box.getarea() << endl; } return 0; This program relies on two other files: Rectangle.h and Rectang.cpp. Before compiling this program, Rectangle.h and Rectangle.cpp must be added to the project. The following steps show you how to set the project up with all three of the existing files as members. 1. Start a new project by following steps 1 9 under the section Starting a New Project, at the beginning of this appendix. Name the project RectangleData. 2. Now you will insert the main C++ source file into the project. Click Project on the menu bar. On the Project menu, click Add Existing Item. Then insert the student disk and use the browse feature to locate the file RectangleData.cpp in the Appendix M folder on the disk. When you locate the file, click it and click the open button (or just double click it.) 3. Now you will insert the Rectangle.cpp source file into the project. Click Project on the menu bar. On the Project menu, click Add Existing Item. Then use the browse feature to locate the file Rectangle.cpp in the Appendix M folder on the student disk. When you locate the file, click it and click the Open button. The file Rectangle.cpp is now a member of your project. 4. Now you will insert the Rectangle.h header file into the project. Repeat the process in step 3 to locate and insert the Rectangle.h file. The Rectangle.h file is now a member of the project. 5. At this point, RectangleData.cpp, Rectangle.cpp, and Rectangle.h are members of the project. You can use the Solution Explorer window to navigate among all the files in the project. Notice the two tabs at the bottom of the Solution Explorer window, as shown in Figure M-19. One is the Solution Explorer tab and the other is the Class View tab. These tabs allow you to switch between a file-oriented view of your project (the Solution Explorer tab) and a class-oriented view of your projected (the Class View tab). Make sure the Solution Explorer tab is selected.

12 Introduction to Microsoft Visual C++.NET 1319 Figure M-19 Solution Explorer tab Class View tab 6. You can expand or contract items in the view by clicking the (minus) sign that appears beside the file folders (a plus sign if the folders are closed). You should see the three files you added to the project shown by default. Double-click on the name RectangleData.cpp. The file is displayed in the editor. (You may display any of these files in the editor by double-clicking their names.) Notice that in Figure M-20 there are tabs with the names of each file in the project just above the editor. You may click any of these tabs to rapidly switch between files in a multi-file project. File tabs Figure M-20

13 1320 Introduction to Microsoft Visual C++.NET Creating a New Multi-File Project If you are creating a new multi-file project (not from existing files), follow steps 1 through 9 under the section Starting a New Project. Type the code for the main source file into the editor. When you are ready to create another source file (such as the header file for a class declaration, or a.cpp file to contain class member function definitions), follow these steps. 1. Click Project on the menu bar, click Add New Item. 2. In the Add New Item box, click the C++ File (.cpp) icon if you are creating a new.cpp file or Header File (.h) if you are creating a new header file. 3. In the File Name text box, enter the name of the file. Extensions are automatically included for the various types. 4. Click the Open button. You will return to the text editor. Enter the code for the new file. Repeat these steps for each new file you wish to add to the project. Removing a File from a Project To remove a file from a project, simply select the file s name in the solution explorer window and press the Delete key. This operation removes the file from the project, but does not delete it from the disk. Where Files are Created When you create a new project, Visual C++.NET creates a project folder with the same name as the project. This is where all of the files associated with the project are normally stored. You can specify the location of the folder when you create the project. (See step 3 of the Starting a New Project section.) For example, suppose we ve created a project named Lab5, and its project folder is at C:\MyProjects\Lab5. All of the C++ source files that you have created for this project will be stored in that folder. In addition, Visual C++.NET will create another folder named Debug, under the C:\MyProjects\Lab5 folder. The Debug folder will contain the project s executable file and its object file(s). It s important to know the location of the project folder when writing code that opens files for input or output. When running a program from the Visual C++ IDE, the project folder is the default location for all data files. For example, suppose our Lab5 project creates a file with the following code: ofstream outputfile("names.txt"); Because we have not specified a path with the file name, the file will be created in the C:\MyProjects\Lab5 project folder. Similarly, if our program attempts to open an existing file

14 Introduction to Microsoft Visual C++.NET 1321 for reading, it will look in the project folder by default. For example, suppose our Lab5 program attempts to open a file with the following statement: ifstream inputfile("names.txt"); Because we have not specified a path, the program will look for the file in the project folder, C:\MyProjects\Lab5. If we want to open a file in a location other than the project folder, we must provide a path as well as a file name. For example, the following statement opens a file named data.txt in the C:\Data folder. ofstream outputfile("c:\\data\\data.txt"); Notice that we ve used two backslashes in the path where you normally use only one. Remember, in a literal string, the compiler interprets the backslash character as the beginning of an escape sequence. In order to represent a backslash as a character in a literal string, you must use two backslashes. Here s another example: ifstream inputfile("a:\\names.txt"); This statement attempts to open the names.txt file in the root folder of drive A.