Experiment 4

I don't really understand the actual usage of static variables in the code. and

 

The algorithm of this question I use the direct method, output a certain number of spaces and characters one by one to form a centered form, I want to know if there is a better algorithm representation.

// 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() {
     for ( int i= 1 ;i<=size;i++ )
    {
        for(int j=1;j<=size-i;j++)
        {
            cout<<' ';
        }
        for(int j=1;j<=2*i-1;j++)
        {
            cout<<symbol;
        }
        cout<<endl;
    }
    // Complement the code to realize the graphic style shown in the "Experiment 4.pdf" document 
}