C++/C 文件二进制读写

C++方式

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include<sys/time.h>
#include<unistd.h>
#include <iostream>
#include <fstream>
#include <string.h>
#include<vector>
#include <string.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
using namespace std;

typedef unsigned long long int uint64;
typedef unsigned int uint32;
int fileread(char* location);

int main() {
cout << "!!!Hello World!!!" << endl; // prints !!!Hello World!!!
char* path =  "/home/lhb/share/data/1/10600000.bin";
fileread(path);
return 0;
}

int fileread( char* location)
{
//读文件
ifstream fin(location, ios::binary);
if(!fin.is_open())
{
printf("Fail to open the file %s",location);
return -1;
}

uint64 p = 0;
float a = 0;
fin.read((char*)&a, sizeof(uint32));
float version = (float) (a);
cout<<"该程序版本为 "<<a<<endl;
fin.read((char*)&p, sizeof(uint32));
int type = (int) (p);
cout<<"该程序类型为 "<<p<<endl;
fin.read((char*)&p, sizeof(uint32));
int dim = (int) (p);//每个数据长度
cout<<"每个数据占"<<dec<<p<<"个bit"<<endl;
fin.read((char*)&p, sizeof(uint32));
int feature_num = (int) (p);//数据个数
cout<<" This file has "<<dec<<p<<" data."<<endl;

//
//	 for( int i = data_counter ; i < (data_counter+feature_num) ; i++)
//	 {
//			fin.read((char *)&szBuf[i][0],4 );
//			for(int j = 1; j < 5; j ++)
//			{
//				fin.read((char *)&szBuf[i][j],8);
//			}
//
//    }
//	data_counter+= feature_num;
fin.close();
return feature_num;
}

*： fin.read的第一个参数必须为char*，所以将变量取&后强制转换后传入。后面循环实现读取数据块。

缺点：只有一个参数控制读入长度，当读取的数据类型和存放的数据类型不一致时只能分多次实现。

http://www.360doc.com/content/10/1207/12/963301_75777844.shtml

/article/2319277.html

C语言方式

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include<sys/time.h>
#include<unistd.h>
#include <iostream>
#include <fstream>
#include <string.h>
#include<vector>
#include <string.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
typedef unsigned int uint32;
typedef unsigned long long int uint64;

using namespace std;

int main()
{
FILE * stream;
stream = fopen("/home/lhb/share/data/1/200000.bin","rb+");
if (stream)
{
cout<<"seccess"<<endl;
}

uint64 p=0;
float a=0;
fread(&a,sizeof(float),1,stream);
cout<<a<<endl;
fread(&p,sizeof(uint32),1,stream);
cout<<p<<endl;
fread(&p,sizeof(uint32),1,stream);
cout<<p<<endl;
fread(&p,sizeof(uint32),1,stream);
cout<<p<<endl;

fclose(stream);

}

*fread()第一个参数为void*，也许要&转换

优点：后面有两个参数控制读取长度，第二参数为每次读取的字节数，第三参数为读取的次数。

http://blog.csdn.net/AresGod/article/details/1852321