C++读取txt文件并统计数字范围个数

txt文件内容：有一万多个整型数字，每个字一行，如图2-记事本.    运行结果如下

代码如下：

// temp_project.cpp: 定义控制台应用程序的入口点。
//

/*
#include "stdafx.h"

int main()
{
printf("------------------");
return 0;
}


*/

//#include "stdafx.h"//我的vs2012编译器版本低，所以直接将此句注释掉了，仍可以运行出来
#include 
#include 
#include 
#include
#include
#define hh printf("\n===================================\n");

using std::string;
using namespace std;

int main()
{
	int count0_2_10 = 0;
	int count11_2_20 = 0;
	int count21_2_30 = 0;
	int count31_2_40 = 0;
	int count41_2_infinite = 0;
	string s = "D:\\2.txt";
	ifstream infile;
	infile.open(s.data());
	assert(infile.is_open());
	string a;
	int temp = 0;
	while (getline(infile,a))
	{
	//	cout << a << endl;
		for ( int i = 0; i < a.length(); i++)
		{
			temp *= 10;
			temp = temp+a.at(i) - 0x30;
		}
		if (temp>=0&&temp<=10)
		{
			count0_2_10++;
		}
		if (temp >=11 && temp <= 20)
		{
			count11_2_20++;
		}
		if (temp >= 21 && temp <= 30)
		{
			count21_2_30++;
		}
		if (temp >= 31 && temp <= 40)
		{
			count31_2_40++;
		}
		if (temp >= 41)
		{
			count41_2_infinite++;
		}
		temp = 0;
	}
	printf("0-10: %d\n  ", count0_2_10);
	printf("11-20: %d\n  ", count11_2_20);
	printf("21-30: %d\n  ", count21_2_30);
	printf("31-40: %d\n  ", count31_2_40);
	printf(">41: %d\n  ", count41_2_infinite);
	infile.close();
	 system("pause");
	return 1;
}