int 价值型追记-time

一个 30 M 的int号码值一次性保存。和读取一次，避免保存为char 种类，进行格转变，格转换时间是非常耗时。

#include <iostream>
#include <fstream>
#include <time.h>
using namespace  std;
#define  MAXNUM  2560*1920
void savedata(char *filename,int *pdata)
{
	ofstream out;
	out.open(filename,ios::binary);
	if(!out.is_open())
		return ;
	for (int i=0;i<MAXNUM;i++)
	{
		pdata[i] = i;
	}
	out.write((char *)pdata,MAXNUM*sizeof(int));
	out.close();
	cout<<endl;
}

void readdata(char *filename,int *pdata,int length)
{
	ifstream ifs(filename,ios::binary);
	if (!ifs)
	{
		cout << "File open error!" << endl; exit(1);
	}

	// 获取文件大小。
	ifs.seekg(0, ios::end);
	streampos pos = (ifs.tellg());
	ifs.seekg(0, ios::beg);  // 注意要将文件指针移动到文件头
	if (pos > 0)
	{
		ifs.read((char*)pdata, pos);
		for (int i = 0; i < pos/4; i++)
		{
			cout << pdata[i];
			cout << endl;
		}
	}
	ifs.close();
}

void main()
{
	int  *pd = new int[MAXNUM];
	memset(pd,'0',MAXNUM);
	for (int i=0;i<MAXNUM;i++)
	{
		pd[i] = i;
	}
	savedata("datat.img",pd);
	int* buff = new int[MAXNUM];
	memset(buff,'0',MAXNUM);
	double start=clock();
	readdata("datat.img",buff,MAXNUM);
	double end=clock();
	cout<<(end - start)<<endl;
	delete[] pd;
	delete[] buff;
	system("pause");

}