Read this Entire Document Before Writing Any Code!!! Problem Overview: What happens when your program asks the user to enter a…

Read this Entire Document Before Writing Any Code!!!
Problem Overview: What happens when your program asks the user to enter a number and they type something that
is all or partly non-numeric? Consider Program 1 below on the left. Five I/O sessions are shown with user input
underlined. Recall that the extraction operator (>>) reads from whitespace to whitespace in the input stream. When
extracting numeric values from the input stream the extraction operator stops when it encounters a non-whitespace
character that can’t be interpreted as part of a number. This can result in a failed input operation and it can leave
unprocessed characters in the stream. For example the ‘a’ in sessions #1 and #3, the “34” characters in #2 and the “- 5” in
session #5 are left unprocessed in the input stream.
One way to avoid the problems encountered with inputting values into numeric variables is to input them into string
variables (objects) using the getline function as shown in Program 2 on the right below. Unfortunately, while this fixes
the problem of leaving unprocessed characters in the input stream, it introduces the new problem that you can’t perform
arithmetic on string objects! You must compute the numeric equivalent of the string value in order to do arithmetic.
//PROGRAM 1
//Input numeric variable value directly
#include [removed]
using namespace std;
int main() {
long num;
cout <[removed]> num;
cout << “You typed ” << num << endl;
return 0;
}
I/O Session #1: Type a number: a
You typed -858993460
I/O Session #2: Type a number: 12 34
You typed 12
I/O Session #3: Type a number: 8a
You typed 8
I/O Session #4: Type a number: -5
You typed -5
I/O Session #5: Type a number: – 5
You typed -858993460
//PROGRAM 2
//Input numeric data into string object
#include [removed]
#include [removed]
using namespace std;
int main() {
string num;
cout << “Type a number: “;
getline(cin,num);
cout << “You typed ” << num << endl;
return 0;
}
I/O Session #1: Type a number: a
You typed a
I/O Session #2: Type a number: 12 34
You typed 12 34
I/O Session #3: Type a number: 8a
You typed 8a
I/O Session #4: Type a number: -5
You typed -5
I/O Session #5: Type a number: – 5
You typed – 5
Program 9 Specifications: You will create a set of C++ source code files that together will declare, implement and
test an InputNumber class. An InputNumber object will accept a user’s input from the console as a string of
characters. The string of characters will then be converted into a corresponding numeric value, or a flag will be set to
indicate that the string of characters did not represent a valid numeric value and so could not be converted. Your
InputNumber class should meet the specifications given in the UML diagram below.
After implementing the no-arg constructor, the input, appropriate setNum and accessor functions, you could write
Program 3 as follows:
//PROGRAM 3
//Input numeric data using an InputNumber object
#include [removed]
#include [removed]
#include “InputNumber.h”
using namespace std;
int main() {
InputNumber num;
cout << “Type a number: “;
num.input();
cout << “You typed ” << num.getInputString() << endl;
if(num.validInputValue())
cout << “What you typed has numeric value ” << num.getValue() << endl;
else
cout << “What you typed is not a valid numeric value. ” << endl;
return 0;
}
HINT 1: New C++ string objects can be assigned the value of a null-terminated C-string char array as follows:
cpp_String = c_char_array;
But if you want to go the other direction you will have to use the page 239 C-string function strcpy and page 312
c_str function as follows: strcpy(c_char_array,cpp_String.c_str());
HINT 2: You may find some of the old-style C-string functions on pages 237-239 useful. For example, you could use
atol (for ascii-to-long) to convert a C-string into an equivalent long value. (Note, if the C-string value is invalid
such as “abc” the converted value will be 0. There is no way to tell if a value of 0 is based on a legitimate string
value or not.) To go the other direction you could use ltoa (for long-to-ascii similar to itoa on page 239), with
radix argument value 10 to indicate you want to convert long number into a base 10 string equivalent.
Alternatively, you might try the stringstream object approach on page 316 to convert a number into a string of
ascii characters.
HINT 3: Feel free to add private utility functions to the class to help you perform the public tasks if desired. For
example, I found it helpful to code a private bool function whose only job was to determine if the value of
inString represented a valid number or not. Expect to have to use a for-loop to visit each character in
inString to perform this task.
HINT 4: Recall from Chapter 9 that you may wish to first write the declaration, implementation and testing code all in one
file as shown in Listing 9.1 on page 286. Once your class is working correctly you can divide the code
appropriately among separate header, implementation, and testing files.
Language Usage Criteria
1 pt • Find an appropriate use for the isdigit() character function described on page 173.
3 pts • Your class declaration code is separated from your class implementation code and your class client testing code.
You will earn both points if the class declaration code is in a separate header file as shown in Listing 9.8 on page
295. If not in a separate file, the class declaration should be above the class implementation code and main() of
the client testing code.
1 pt • Find an appropriate use for the atol() C-string function described on page 239.
1 pt • Find an appropriate use for the ltoa() C-string function which is exactly like the itoa() function described on
page 239 and in HINT 2 above or use the stringstream technique shown on page 316
2 pts • Find an appropriate use for at least two of the string functions and/or operators mentioned in Chapter 10.
3 pts • The tester program contains a void displayNum function that accepts a reference to a InputNumber object
and any other parameters you may wish to use. Whenever your tester program wants to display the contents of
an InputNumber object it should call the displayNum function.
3 pts • The tester program declares and uses an array of InputNumber objects. You may have other InputNumber
objects besides those in the array, but you are to demonstrate the ability declare and access effectively an array
of objects.
14 pts for Language Usage
Functionality Criteria
1 pt • The no-arg constructor sets numValue to 0, inString to “0” and validInput to true.
1 pt • The second constructor calls the appropriate setNum function with the parameter value as the argument.
1 pt • The third constructor calls the appropriate setNum function with the parameter value as the argument.
1 pt • The getValue() function returns the current value of the numValue data field.
1 pt • The validInputValue() function returns the current value of the validInput data field. NOTE: Not all “get”
functions have to have “get” as part of their name!
1 pt • The getInString() function returns the current value of the inString data field.
1 pt • The input() function uses the getline() function descibed on pages 315-316 to input what the user typed into a
local string object. It then calls the appropriate setNum function with the user’s input as the argument.
3 pts • The commaString() function returns a string representation of the number containing commas if and where
appropriate. E.g. If inString is “1000” commaString() returns a string with the value “1,000”; if inString
is “1000000” commaString() returns a string with the value “1,000,000”; etc. Note: commaString() does
not change the value of inString!
3 pts • The first setNum() function sets numValue to the newNum parameter’s value, inString to the string
equivalent of numValue, and validInput to true.
3 pts • The second setNum() function sets inString to the strNum parameter value, and numValue to the best
possible numeric equivalent of inString. If there are no errors interpreting inString as a number,
validInput is set too true, otherwise it is set to false.
Checkpoint Stub Code: Just assume that the strNum parameter represents a valid numeric value.
5 pts • The InputNumber class code correctly identifies whenever inString is set to a non-numeric value as follows:
○ Any spaces at the beginning and ending of the string are ok, but…
○ …spaces in the middle of the string cause it to be invalid.
That is, “ 123 “ is a valid numeric string value, but “1 23” is not.
○ Aside from leading and trailing spaces, no other non-digit characters are valid in the string…
○…except that ‘-‘ (minus sign) is allowed to precede the first digit in the string.
That is, “-45” is ok, but “4-5” is not.
6 pts • The client testing code exhaustively tests all of the functions of the InputNumber class. How do the functions of
the class behave when they are “fed” good data? What about bad data?
Checkpoint Tester Code: Just use Program 3 below the InputNumber UML above.
27 pts for Functionality
Style Criteria
1 pt • The first lines of each source code file contain comments that include the programmer name(s) and a brief
description of the purpose of the code in the file.
1 pt • Use a consistent and appropriate indentation style as discussed in 2.12.3 on page 59. Follow the indentation style
used in the sample code throughout the book.
1 pt • Use appropriate spacing and blank lines to enhance program readability as discussed in 2.12.3 on page 59.
1 pt • All code is necessary to the proper functioning of the program; e.g. no unused variable declarations, no
unnecessarily complex code.
4 pts for Style
Total Lab 9 points possible: 45
Turn in
Send your header, implementation and client tester files as email attachments. The subject field of the email should say
CS 210 Lab 9. The message field of the email should contain the programmer name(s). If you are programming in a
team, be sure to cc your teammates.