Classes and Objects

Contents

Fraction Example (using struct)

main.cpp
​x
 
#include <iostream>
using namespace std;
​
/**
 * gcd(a, 0) = a
 * gcd(a, b) = gcd(b, a mod b)
 */
int gcd(int a, int b)
{
    if (b==0)
        return a;
    return gcd(b, a%b);
}
​
/**
 * lcm = (a*b)/gcd(a,b)
 */
int lcm(int a, int b)
{
    auto local_gcd = gcd(a,b);
​
    if (local_gcd == 0)
        return 0;
    return a / gcd(a,b) * b;
}
​
struct Fraction
{
    int numerator;
    int denominator;
};
​
Fraction add_fractions(Fraction lhs, Fraction rhs)
{
    auto common_den = lcm(lhs.denominator, rhs.denominator);
​
    lhs.numerator = lhs.numerator * common_den/lhs.denominator;
    rhs.numerator = rhs.numerator * common_den/rhs.denominator;
    lhs.denominator = rhs.denominator = common_den;
​
    Fraction sum;
    sum.numerator = rhs.numerator + lhs.numerator;
    sum.denominator = common_den;
    
    return sum;
}
​
void display_fraction(const Fraction& f)
{
    cout << f.numerator << "/" << f.denominator;
}
​
int main()
{
    Fraction f1 = {1, 2};
    Fraction f2;
    f2.numerator = 1;
    f2.denominator = 3;
​
    Fraction sum = add_fractions(f1, f2);
​
    display_fraction(f1);
    cout << " + ";
    display_fraction(f2);
    cout << " = ";
    display_fraction(sum);
    cout << endl;
​
    return 0;
}

Fraction Example (using class)

main.cpp
 
// compilation command:
// g++ -std=c++11 -o prog fraction.cpp main.cpp
#include <iostream>
using namespace std;
​
#include "fraction.h"
​
int main()
{
    Fraction f1(1, 3);
    Fraction f2(2, 3);
​
    Fraction sum = f1.add_fractions(f2);
​
    f1.display();
    cout << " + ";
    f2.display();
    cout << " = ";
    sum.display();
    cout << endl;
​
    return 0;
}
fraction.h
 
#ifndef FRACTION_H
#define FRACTION_H
​
class Fraction
{
public:
    Fraction(int num, int den);
    Fraction add_fractions(Fraction rhs);
    void display();
​
private:
    int numerator;
    int denominator;
​
};
​
#endif
fraction.cpp
 
#include <iostream>
using namespace std;
​
#include "fraction.h"
​
/**
 * gcd(a, 0) = a
 * gcd(a, b) = gcd(b, a mod b)
 */
int gcd(int a, int b)
{
    if (b==0)
        return a;
    return gcd(b, a%b);
}
​
/**
 * lcm = (a*b)/gcd(a,b)
 */
int lcm(int a, int b)
{
    auto local_gcd = gcd(a,b);
​
    if (local_gcd == 0)
        return 0;
    return a / gcd(a,b) * b;
}
​
​
Fraction::Fraction(int num, int den)
{
    numerator = num;
    denominator = den;
}
​
Fraction Fraction::add_fractions(Fraction rhs)
{
    Fraction lhs(numerator, denominator);
    auto common_den = lcm(lhs.denominator, rhs.denominator);
​
    lhs.numerator = lhs.numerator * common_den/lhs.denominator;
    rhs.numerator = rhs.numerator * common_den/rhs.denominator;
    lhs.denominator = rhs.denominator = common_den;
​
    Fraction sum(1, 1);
    sum.numerator = rhs.numerator + lhs.numerator;
    sum.denominator = common_den;
    
    return sum;
}
​
void Fraction::display()
{
    cout << numerator << "/" << denominator;
}