Object and Generic Programming in C++ Laboratory Exercise 9 Solution

Task One: String Stream (0.6 marks)

Use ostringstream and istringstream to implement the following two functions in a file stringIO.cpp by assuming that the operators << and have been overloaded for type T.  template<class T string toString (T value); // convert a value into a string

 

 template <class T

 

T toValue(string str); // extract the value from a string

 

Defined a class Student in a file Student.h and implemented the member functions  in a file

 

Student.cpp. The class Student can be defined like following class Student { private:

 

string firstname; string lastname; int id; // student number float gpa;

 

public:

 

// all necessary functions to be defined here … …

 

};

 

Implement a main() function in stringIO.cpp to test the two functions in the cases where T is integer, double and class Student.

 

 

 

You need to define and implement the student class properly in order to test the two template functions and assume the input string for the student class is in the following format.

 

 

 

First-name:last-name:student-number:gpa

 

 

 

For example:

 

John:Anderson:1234567:6.35

 

 

 

Testing:

 

 

 

Compile the program in this task by:

 

CC –o task1 stringIO.cpp Student.cpp

 

 

 

Run the program (You may use different values)

 

./task1

 

Input an integer: 12345678

 

Integer to string: 12345678

 

String to integer: 12345678

 

Input a double: 3214.654

 

Double to string: 3214.65

 

String to double: 3214.65

 

Input a student record (first-name:last-name:number:gpa): David:Smith:1234567:3.65 Student to string:  David:Smith:1234567:3.65 String to Student:

 

David:Smith:1234567:3.65

 

 

 

Note: The outputs above indicate different types of data.

 

 

 

Task two: Compare two vectors (0.4 marks)

The program vectorCompare.cpp intends to implement and test a predicate function:

 

bool same_elements(vector<int a, vector<int b)

 

that checks whether two vectors have the same elements with the same multiplicities. For example, “1 4 9 16 9 7 4 9 11” and “11 1 4 9 16 9 7 4 9” would be considered identical, but “1 4 9 16 9 7 4 9 11” and “11 11 7 9 16 4 1” would not.

 

And a function that removes duplicates from a vector:

 

void remove_duplicates(vector<int& a)

 

Complete the implementation of these two functions in the given vectorCompare.cpp file . You will probably need one or more helper functions for the implementation. Place the helper functions in the specified place. Complete the main function and test your implementation.

 

 

 

 

 

 

 

pgm

 

The PGM format is designed to be extremely easy to learn and write programs for. A PGM image represents a grayscale graphic image. For most purposes, a PGM image can just be thought of an array of arbitrary integers, and all the programs in the world that think they're processing a grayscale image can easily be tricked into processing something else.

 

The name "PGM" is an acronym derived from "Portable Gray Map."  Each PGM image consists of the following:

 

A "magic number" for identifying the file type. A pgm image's magic number is the two characters "P5".

Whitespace (blanks, TABs, CRs, LFs).

A width, formatted as ASCII characters in decimal.

 

A height, again in ASCII decimal.

 

The maximum gray value (Maxval), again in ASCII decimal. Must be less than 65536, and more than zero.

Newline or other single whitespace character.

A raster of Height rows, in order from top to bottom. Each row consists of Width gray values, in order from left to right. Each gray value is a number from 0 through Maxval, with 0 being black and Maxval being white. Each gray value is represented in pure binary by either 1 or 2 bytes. If the Maxval is less than 256, it is 1 byte. Otherwise, it is 2 bytes. The most significant byte is first.

A row of an image is horizontal. A column is vertical. The pixels in the image are square and contiguous.

 

Each gray value is a number proportional to the intensity of the pixel. A value of zero is black. A value of Maxval represents white and the most intense value in the image and any other image to which the image might be compared.

Characters from a "#" to the next end-of-line, before the maxval line, are comments and are ignore.