an introduction to programming with c++ fifth edition chapter 12 string manipulation

An Introduction to Programming with C++

Fifth Edition

Chapter 12String Manipulation

An Introduction to Programming with C++, Fifth Edition 2

Objectives

• Determine the number of characters contained in a string

• Remove characters from a string

• Access characters contained in a string

• Replace characters in a string

• Insert characters within a string


Objectives (continued)

• Search a string for another string

• Compare a portion of a string variable’s contents to another string

• Duplicate a character within a string variable

• Concatenate strings

• Perform string manipulation in .NET C++


Concept Lesson

• Manipulating Strings

• Determining the Number of Characters Contained in a String

• Removing Characters from a String

• Accessing Characters Contained in a String

• Replacing Characters in a String


Concept Lesson (continued)

• Inserting Characters within a String

• Searching a String

• Comparing a Portion of a String with Another String

• Duplicating a Character within a String Variable

• Concatenating Strings


Manipulating Strings

• Programs often need to manipulate string data– For example

• Verify that an inventory part number begins with a specific letter

• Determine whether the last three characters in an employee number are valid


Determining the Number of Characters Contained in a String

• Use length() to determine the number of characters in a string variable– Or use size()

• Syntax: string.size()


Determining the Number of Characters Contained in a String (continued)


Removing Characters from a String

• Use erase() to remove one or more characters located anywhere in a string variable– Syntax in Figure 12-2

• subscript and count arguments can be numeric literal constants or the names of numeric variables


Removing Characters from a String (continued)


Accessing Characters Contained in a String

• You may need to determine whether a specific letter appears as the third character in a string

• Or, you may need to display only the string’s first five characters

• Use substr() to access any number of characters contained in a string variable– “substr” stands for “substring”


Accessing Characters Contained in a String (continued)


Replacing Characters in a String

• Use replace() to replace a sequence of characters in a string variable with another sequence of characters– Syntax in Figure 12-4

• replacementString can be a string literal constant or the name of a string variable


Replacing Characters in a String (continued)


Inserting Characters within a String

• insert() inserts characters within a string


Searching a String

• Use find() to search a string variable to determine if it contains a sequence of characters


Searching a String (continued)


Comparing a Portion of a String with Another String

• Use the comparison operators to compare strings– >, >=, <, <=, ==, and !=– E.g., while (name != "DONE")

• To compare a portion of one string with another string, use compare()


Comparing a Portion of a String with Another String (continued)


Duplicating a Character within a String Variable

• Use assign() to duplicate a character a specified number of times


Duplicating a Character within a String Variable (continued)


Concatenating Strings

• Connecting (or linking) strings together is called concatenating

• In C++, you concatenate strings using the concatenation operator– The + sign


It is easier to use:hyphens.assign(5, '-');

Concatenating Strings (continued)


Summary

• String manipulation is a common programming task


Summary (continued)


Application Lesson: Using String Manipulation in a C++ Program

• Lab 12.1: Stop and Analyze

• Lab 12.2– Program that allows two students to play a simplified

version of the Hangman Game on the computer

• Lab 12.3– Modify program so that it allows player 1 to enter a

word of any length

• Lab 12.4: Desk-Check Lab

• Lab 12.5: Debugging Lab

an introduction to programming with c++ fifth edition chapter 12 string manipulation

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