C++统计一个文件中每个数字字符(0~9)出现的次数

现在有一个文本文件，请写一个程序，统计该文件中每个数字字符(0~9)出现的次数，并将统计结果打印到屏幕上。

#include<iostream>
#include<fstream>
using namespace std;
int main()
{
	ifstream fopen("D:\\test.txt");
	if (!fopen)
	{
		cout << "The file can not be opened" << endl;
		return -1;
	}
	int arr[10] = { 0 };
	char ch;
	while (!fopen.eof())
	{
		ch=fopen.get();
		switch (ch)
		{
		case '0':arr[ch - '0']++; break;
		case '1':arr[ch - '0']++; break;
		case '2':arr[ch - '0']++; break;
		case '3':arr[ch - '0']++; break;
		case '4':arr[ch - '0']++; break;
		case '5':arr[ch - '0']++; break;
		case '6':arr[ch - '0']++; break;
		case '7':arr[ch - '0']++; break;
		case '8':arr[ch - '0']++; break;
		case '9':arr[ch - '0']++; break;
		default:
			break;
		}
	}
	for (int i = '0'; i <='9'; ++i)
	{
		cout << i << endl;
		cout << (char)i << "出现的次数：" << arr[(char)i - '0'] << endl;
	}
	return 0;
}