80分代码：

#include<bits/stdc++.h>
#include<cstdio>
using namespace std;
long long a,b,d;
char c; 
int main()
{
	cin>>a>>b>>c>>d;
	if(d!=0)
	{
		for(int i=1;i<=a;i++)
		{
			for(int j=1;i<=b;j++)
			{
				cout<<c;
			}
			cout<<endl;
		}
	}
	else
	{
        for(int i=1;i<=b;i++)
		{
		    cout<<c;	
		}
        cout<<endl;
        for(int i=1;i<a-1;i++)
		{
            cout<<c;
            for(int j=1;j<b-1;j++)
			{
				cout<<" ";
			}
            cout<<c<<endl;
        }
        for(int i=0;i<b;i++)
		{
			cout<<c;
		}
    }
	return 0;
}

AC代码：

#include <bits/stdc++.h>
#include <cstdio>
using namespace std;
int a,b,f;
char c;
int main()
{
	cin >> a >> b >> c >> f;
	if (f != 0)
	{
		for (int i = 1;i <= a; i ++)
		{
			for (int j = 1;j <= b;j ++)
			{
				cout << c;
			}
			puts ("");
		}
		return 0;
	}
	for (int i = 1;i <= b;i ++)
	{
		cout << c;
	}
	puts ("");
	for (int i = 2;i < a;i ++)
	{
		cout << c;
		for (int i = 2;i < b;i ++)
		{
			cout << " ";
		}
		cout << c << endl;
	}
	for (int i = 1;i <= b;i ++)
	cout << c;
	return 0;
}