Can be removed through the use of using statements Standard output stream object – std::cout » “Connected” to screen » Defined in input/output stream header file <iostream>
10 First Program in C++: Printing a Line of Text (Cont.) Stream insertion operator << – Value to right (right operand) inserted into left operand – Example » std::cout << "Hello"; Inserts the string "Hello" into the standard output – Displays to the screen Escape characters – A character preceded by "\" » Indicates “special” character output – Example » "\n" Cursor moves to beginning of next line on the screen
11 Common Programming Error 2.2 Omitting the semicolon at the end of a C++ statement is a syntax error. (Again, preprocessor directives do not end in a semicolon.) A syntax error occurs when the compiler encounters code that violates C++’s language rules (i.e., its syntax). The compiler normally issues an error message to help the programmer locate and fix the incorrect code. (cont…)
12 Common Programming Error 2.2 Syntax errors are also called compiler errors, compile-time errors or compilation errors, because the compiler detects them during the compilation phase. You will be unable to execute your program until you correct all the syntax errors in it. As you’ll see, some compilation errors are not syntax errors.
13 First Program in C++: Printing a Line of Text (Cont.) return statement – One of several means to exit a function – When used at the end of main » The value 0 indicates the program terminated successfully » Example return 0;
14 Good Programming Practice 2.3 Many programmers make the last character printed by a function a newline ( \n ). This ensures that the function will leave the screen cursor positioned at the beginning of a new line.
15 Escape sequence Description \n Newline. Position the screen cursor to the beginning of the next line. \t Horizontal tab. Move the screen cursor to the next tab stop. \r Carriage return. Position the screen cursor to the beginning of the current line; do not advance to the next line. \a Alert. Sound the system bell. \\ Backslash. Used to print a backslash character. \' Single quote. Use to print a single quote character. \" Double quote. Used to print a double quote character. Escape sequences
16 Good Programming Practice 2.4 Indent the entire body of each function one level within the braces that delimit the body of the function. This makes a program’s functional structure stand out and helps make the program easier to read. Set a convention for the size of indent you prefer, then apply it uniformly. The tab key may be used to create indents, but tab stops may vary.
17 Modifying Our First C++ Program Two examples – Print text on one line using multiple statements (Fig. 2.3) » Each stream insertion resumes printing where the previous one stopped – Print text on several lines using a single statement (Fig. 2.4) » Each newline escape sequence positions the cursor to the beginning of the next line » Two newline characters back-to-back outputs a blank line
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