fourth time 2

#ifndef GRAPH_H
#define GRAPH_H

// Declaration of class Graph 
class Graph {
     public :
        Graph( char ch, int n);    // Constructor with parameters 
        void draw();      // Draw graph 
    private :
         char symbol;
         int size;
};


#endif

// The implementation of class graph 
 
#include " graph.h "  
#include <iostream>
 using  namespace std;

// Implementation of constructor with parameters 
Graph::Graph( char ch, int n): symbol(ch), size(n) {
}


// implementation of member function draw()
 // Function: draw size line, display the specified graphic style with the character as symbol 
 //        size and symbol are private member data of class Graph 
void Graph::draw() {
     // Complement code, Implement the graphic style shown in the "Experiment 4.pdf" document 
    int i,j,k;
     for (i= 1 ;i<=size;i++ )
    {
        for(j=1;j<=size-i;j++)
        {
            cout<<' ';
        }
        for(k=1;k<=2*i-1;k++)
        {
            cout<<symbol;
        }
        for(j=1;j<=size-i;j++)
        {
            cout<<' ';
        }
        cout<<endl;
    }    
}

#include <iostream>
#include "graph.h"
using namespace std;


int main() {
    Graph graph1( ' * ' , 5 ), graph2( ' $ ' , 7 ) ;   // Define Graph class objects graph1, graph2 
    graph1.draw(); // Call the public interface draw() through the object graph1 to draw the graph on the screen 
    graph2.draw(); // Draw the graph on the screen by calling the public interface draw() through the object graph2
    
    return 0; 
}

// Declaration of class Fraction 
class Fraction {
     public :    
        Fraction();             // constructor 
        Fraction( int t, int b); // overload 
        Fraction( int t);        // overload 
        void show();            // show function 
        void add(Fraction &f1); // add 
        void min(Fraction &f1); // Subtract 
        void mul(Fraction &f1); // Multiply 
        void div(Fraction &f1); // Division 
        void compare(Fraction f1, Fraction f2); // Compare 
    private :
         inttop;    // numerator 
        int bottom; // denominator 
};

#include "Fraction.h" 
#include <iostream>
using namespace std;

// Fraction function 
Fraction::Fraction() {     
    top = 0; bottom = 1;
}
Fraction::Fraction(int t, int b) { 
    top = t; bottom = b;
}
Fraction::Fraction(int t) {        
    top = t; bottom = 1;
}
 void Fraction::add(Fraction &f1) {   //加法
     Fraction f2;
     f2.top = top * f1.bottom + f1.top*bottom;
     f2.bottom = bottom * f1.bottom;
     f2.show();
}
 void Fraction::min(Fraction &f1) {    //减法
     Fraction f2;
     f2.top = top * f1.bottom - f1.top*bottom;
     f2.bottom = bottom * f1.bottom;
     f2.show();
 }
 void Fraction::mul(Fraction &f1) {    //乘法
     Fraction f2;
     f2.top =top*f1.top;
     f2.bottom =bottom*f1.bottom;
     f2.show();
 }
 void Fraction::div(Fraction &f1) {    //除法
     Fraction f2;
     f2.top =top*f1.bottom;
     f2.bottom = bottom * f1.top;
     f2.show();
 }
 void Fraction::show(){          //show函数
    cout<<top<<"/"<<bottom<<endl;
}    
 void Fraction::compare(Fraction f1, Fraction f2) {    //比较
     float a,b;
     a = f1.top * f1.bottom; 
     b = f2.top * f2.bottom;
     if (a <= b) { 
     cout << f1.top << "/" << f1.bottom << "<="; 
     f2.show(); cout << endl; 
     }
     if (a > b) { 
     cout << f1.top << "/" << f1.bottom << ">"; 
     f2.show(); cout << endl;
     }
 }

#include <iostream>
#include "Fraction.h"
using namespace std;

intmain ()
{
    Fraction f1;
    Fraction f2(5);
    Fraction f3(3, 4);
    f1.show();
    f2.show();
    f3.show();
    f2.min(f3);    // subtract 
    f2.add(f3);    // add 
    f2.mul(f3);    // multiply 
    f2.div(f3);    // divide 
    f2.compare(f2, f3);   / / compare 
    return  0 ;
}

Question 1: There are n lines in total, there are ni spaces before and after the i-th line, and 2i-1 symbols.

In this experiment, I can't solve the problem alone, and I am not proficient in the application of classes, so I need to practice more.