2.3. Modifying Our First C++ Program

This section continues our introduction to C++ programming with two examples, showing how to modify the program in Fig. 2.1 to print text on one line by using multiple statements, and to print text on several lines by using a single statement.

Printing a Single Line of Text with Multiple Statements

Welcome to C++! can be printed several ways. For example, Fig. 2.3 performs stream insertion in multiple statements (lines 8–9), yet produces the same output as the program of Fig. 2.1. [Note: From this point forward, we use a white background in the code table to highlight the key features each program introduces.] Each stream insertion resumes printing where the previous one stopped. The first stream insertion (line 8) prints Welcome followed by a space, and the second stream insertion (line 9) begins printing on the same line immediately following the space.

 1   // Fig. 2.3: fig02_03.cpp
 2   // Printing a line of text with multiple statements.
 3   #include <iostream> // allows program to output data to the screen
 4
 5   // function main begins program execution
 6   int main()
 7   {
 8     std::cout << "Welcome "; 
 9     std::cout << "to C++!\n";
10
11     return 0; // indicate that program ended successfully
12
13   } // end function main

Welcome to C++!

Printing Multiple Lines of Text with a Single Statement

A single statement can print multiple lines by using newline characters, as in line 8 of Fig. 2.4. Each time the \n (newline) escape sequence is encountered in the output stream, the screen cursor is positioned to the beginning of the next line. To get a blank line in your output, place two newline characters back to back, as in line 8.

 1   // Fig. 2.4: fig02_04.cpp
 2   // Printing multiple lines of text with a single statement.
 3   #include <iostream> // allows program to output data to the screen
 4
 5   // function main begins program execution
 6   int main()
 7   {
 8      std::cout << "Welcome\nto\n\nC++!\n";
 9
10      return 0; // indicate that program ended successfully
11
12   } // end function main

 Welcome
 to

 C++!