An Introduction to Programming with C++ Sixth Edition

1. An Introduction to Programming with C++Sixth Edition Chapter 13 Strings

2. Objectives • Utilize string memory locations in a program • Get string input using the getline function • Ignore characters using the ignore function • Determine the number of characters in a string • Access the characters in a string • Search a string An Introduction to Programming with C++, Sixth Edition

3. Objectives (cont’d.) • Remove characters from a string • Replace characters in a string • Insert characters within a string • Duplicate characters within a string • Concatenate strings An Introduction to Programming with C++, Sixth Edition

4. The string Data Type • The string data type is not a fundamental data type in C++ • Added to C++ through use of string class • To use the string class, a program must contain the #include <string> directive • You can use the string class to create string variables or string named constants • Memory locations of type string are initialized with string literal constants—0 or more characters enclosed in double quotation marks (“”) An Introduction to Programming with C++, Sixth Edition

5. The string Data Type (cont’d.) Figure 13-1 How to declare and initialize string variables and named constants An Introduction to Programming with C++, Sixth Edition

6. The Creative Sales Program • Program gets a salesperson’s name and sales amount from keyboard • Calculates salesperson’s bonus and displays salesperson’s name and bonus amount • Extraction operator can be used to get string input from keyboard • Stops reading characters when it encounters a white-space character (blank, tab, or newline character) An Introduction to Programming with C++, Sixth Edition

7. The Creative Sales Program (cont’d.) Figure 13-2 Problem specification and IPO chart for the Creative Sales program An Introduction to Programming with C++, Sixth Edition

8. The Creative Sales Program (cont’d.) Figure 13-3 How to use the extraction operator (>>) to get string input An Introduction to Programming with C++, Sixth Edition

9. The getline Function • The getline function obtains string data from the keyboard and stores it in a string variable • Syntax is: getline(cin, stringVariableName [, delimiterCharacter]); • Three actual arguments (first two required): • cin argument refers to computer keyboard • stringVariableName argument is name of a string variable in which to store input • Optional delimiterCharacter indicates character that immediately follows last character of string An Introduction to Programming with C++, Sixth Edition

10. The getline Function (cont’d.) • Function will continue to read characters entered at keyboard until it encounters a delimiter character • Default delimiter character is newline character • When the function encounters a delimiter character, it discards the character—process called consuming the character • Newline character is designated by ‘\n’ • Backslash is called an escape character • Backslash and character following it are called an escape sequence An Introduction to Programming with C++, Sixth Edition

11. Figure 13-4 How to use the getline function to get string input from the keyboard An Introduction to Programming with C++, Sixth Edition

12. Figure 13-5 Creative Sales program An Introduction to Programming with C++, Sixth Edition

13. The getline Function (cont’d.) Figure 13-6 Sample run of the Creative Sales program An Introduction to Programming with C++, Sixth Edition

14. Figure 13-7 Partial Creative Sales program showing the modifications Figure 13-8 Results of running the modified Creative Sales program An Introduction to Programming with C++, Sixth Edition

15. The ignore Function • The ignore function instructs the computer to read and ignore characters stored in the cin object by consuming (discarding) them • Syntax is: • cin.ignore([numberOfCharacters][,delimiterCharacter]); • Has two actual arguments, both optional: • numberOfCharacters argument is maximum number of characters function should consume (default is 1) • delimiterCharacter argument stops ignore function from reading and discarding any more characters when consumed An Introduction to Programming with C++, Sixth Edition

16. Figure 13-9 How to use the ignore function An Introduction to Programming with C++, Sixth Edition

17. Figure 13-10 Modified Creative Sales program with the ignore function An Introduction to Programming with C++, Sixth Edition

18. The ignore Function (cont’d.) Figure 13-11 Sample run of the modified Creative Sales program with the ignore function An Introduction to Programming with C++, Sixth Edition

19. The ZIP Code Program • Program reads in a string from the user and verifies that it contains exactly five characters • If string contains exactly five characters, program displays “Valid length” • Otherwise, displays “Invalid length” An Introduction to Programming with C++, Sixth Edition

20. The ZIP Code Program (cont’d.) Figure 13-12 Problem specification and IPO chart for the ZIP Code program An Introduction to Programming with C++, Sixth Edition

21. Determining the Number of Characters Contained in a string Variable • You use string class’s length function to determine the number of characters in a string variable • Syntax is: • string.length() • Returns number of characters contained in string An Introduction to Programming with C++, Sixth Edition

22. Determining the Number of Characters Contained in a string Variable (cont’d.) Figure 13-13 How to use the length function An Introduction to Programming with C++, Sixth Edition

23. Figure 13-13 How to use the length function (cont’d.) An Introduction to Programming with C++, Sixth Edition

24. Figure 13-14 The ZIP code program An Introduction to Programming with C++, Sixth Edition

25. Determining the Number of Characters Contained in a string Variable (cont’d.) Figure 13-15 Sample run of the ZIP code program An Introduction to Programming with C++, Sixth Edition

26. Accessing the Characters Contained in a string Variable • The substr function allows you to access any number of characters contained in a string variable by returning the specified characters • Syntax is: • string.substr(subscript[, count]) • Has two arguments (first is required): • subscript argument represents subscript of first character you want to access in string • count argument is number of characters to return after character specified by subscript An Introduction to Programming with C++, Sixth Edition

27. Accessing the Characters Contained in a string Variable (cont’d.) • If you omit count argument, function returns all characters from subscript position through end of string • A string is equivalent to a one-dimensional array of characters • Each character has a unique subscript that indicates character’s position in the string An Introduction to Programming with C++, Sixth Edition

28. Accessing the Characters Contained in a string Variable (cont’d.) Figure 13-16 How to use the substr function An Introduction to Programming with C++, Sixth Edition

29. Figure 13-16 How to use the substr function (cont’d.) An Introduction to Programming with C++, Sixth Edition

30. Accessing the Characters Contained in a string Variable (cont’d.) Figure 13-17 Modified problem specification for the ZIP code program An Introduction to Programming with C++, Sixth Edition

31. Figure 13-17 Modified IPO chart information and C++ instructions for the ZIP code program (cont’d.) An Introduction to Programming with C++, Sixth Edition

32. Figure 13-17 Modified IPO chart information and C++ instructions for the ZIP code program (cont’d.) An Introduction to Programming with C++, Sixth Edition

33. Accessing the Characters Contained in a string Variable (cont’d.) Figure 13-17 Modified IPO chart information and C++ instructions for the ZIP code program (cont’d.) An Introduction to Programming with C++, Sixth Edition

34. Accessing the Characters Contained in a string Variable (cont’d.) Figure 13-18 Modified ZIP code program An Introduction to Programming with C++, Sixth Edition

35. Figure 13-18 Modified ZIP code program (cont’d.) An Introduction to Programming with C++, Sixth Edition

36. Accessing the Characters Contained in a string Variable (cont’d.) Figure 13-19 Sample run of the modified ZIP code program An Introduction to Programming with C++, Sixth Edition

37. The Rearranged Name Program • Program allows user to enter a person’s first and last names, separated by a space • Displays the person’s last name followed by a comma, a space, and the person’s first name • Searches the input string for the space that separates the first and last names An Introduction to Programming with C++, Sixth Edition

38. Figure 13-20 Problem specification and IPO chart for the rearranged name program An Introduction to Programming with C++, Sixth Edition

39. Searching the Contents of a string Variable • You use the find function to search contents of a string variable to determine whether it contains a specific sequence of characters • Syntax is: • string.find(searchString, subscript) • searchString argument is astring for which you are searching within string • subscript argument specifies starting position for the search An Introduction to Programming with C++, Sixth Edition

40. Searching the Contents of a string Variable (cont’d.) • find function performs a case-sensitive search (uppercase and lowercase letters are not equivalent) • When searchString is contained within string, function returns an integer that indicates beginning position of searchString within string • Function returns -1 when searchString is not contained within string An Introduction to Programming with C++, Sixth Edition

41. Searching the Contents of a string Variable (cont’d.) Figure 13-21 How to use the find function An Introduction to Programming with C++, Sixth Edition

42. Figure 13-21 How to use the find function (cont’d.) An Introduction to Programming with C++, Sixth Edition

43. Figure 13-22 Rearranged name program An Introduction to Programming with C++, Sixth Edition

44. Searching the Contents of a string Variable (cont’d.) Figure 13-23 Sample run of the rearranged name program An Introduction to Programming with C++, Sixth Edition

45. The Annual Income Program • Program allows the user to enter a company’s annual income • Removes any commas and spaces from user’s entry before displaying annual income An Introduction to Programming with C++, Sixth Edition

46. The Annual Income Program (cont’d.) Figure 13-24 Problem specification for the annual income program An Introduction to Programming with C++, Sixth Edition

47. Figure 13-24 IPO chart for the annual income program (cont’d.) An Introduction to Programming with C++, Sixth Edition

48. Removing Characters from a string Variable • You can use the erase function to remove one or more characters from a string variable • Syntax is: • string.erase(subscript[, count]); • subscript is position of first character you want to remove • Optional count argument is an integer that specifies number of characters you want removed • If you omit count, function removes all characters from subscript through end of string An Introduction to Programming with C++, Sixth Edition

49. Removing Characters from a string Variable (cont’d.) Figure 13-25 How to use the erase function An Introduction to Programming with C++, Sixth Edition

50. Figure 13-25 How to use the erase function (cont’d.) An Introduction to Programming with C++, Sixth Edition