C/C++读写文本文件、二进制文件[转]

参考连接：https://blog.youkuaiyun.com/nichengwuxiao/article/details/78789225

#include <stdio.h> //包含c文件读写
#include <fstream> //包含c++文件读写
#include <iostream>
#include <vector>
#include <iomanip>
using namespace std;

/*
1. C语言读写文件均通过FILE指针执行操作，其中文本文件的读写用fprintf,fscanf，二进制文件的读写用fread,fwrite
2. C++读写文件通过fstream、ifstream、ofstream进行操作，文本文件用<< 和 >> 进行读写，二进制文件用read和write进行读写
*/
/************************************************************************/
/* C                                                                     */
/************************************************************************/
/*
C 文本写入
*/
int TextWrite_C(){
	int index[50];
	double x_pos[50],y_pos[50];
	//向数组填充数据
	for (int i=0;i<50;i++)
	{
		index[i] = i;
		x_pos[i] = rand()%1000 * 0.01;
		y_pos[i] = rand()%2000 * 0.01;
	}

	//写入数据
	FILE *pFileWriter = fopen("txt_out_c.txt","w");
	if (NULL == pFileWriter)
	{
		printf("写文件失败!\n");
		return -1;
	}
	for (int i = 0;i<50;i++)
	{
		fprintf(pFileWriter,"%03d\t%4.6lf\t%4.6lf\n",index[i],x_pos[i],y_pos[i]);
	}
	fclose(pFileWriter);
	return 0;
}

/*
C 文本读取
*/
int TextRead_C(){
	FILE *pFileRead = fopen("txt_out_c.txt","r");
	if (NULL == pFileRead)
	{
		printf("打开%s失败!","txt_out_c.txt");
		return -1;
	}

	vector<int> index;
	vector<double> x_pos;
	vector<double> y_pos;
	
	int mode = 1;
	printf("mode=1:按字符读取\nmode=2:按行读取\nmode=3:按数据格式读取");
	scanf("%d",&mode);
	if (1==mode)
	{
		char ch;
		while(EOF !=(ch = fgetc(pFileRead))){
			printf("%c",ch);
		}
	}else if (2 == mode)
	{
		char line[1024];
		memset(line,0,1024);
		while(!feof(pFileRead)){
			fgets(line,1024,pFileRead);
			printf("%s\n",line);
		}
	}else if (3 == mode)
	{
		int index_tmp;
		double x_tmp,y_tmp;
		while (!feof(pFileRead))
		{
			fscanf(pFileRead,"%d%lf%lf\n",&index_tmp, &x_tmp, &y_tmp);
			index.push_back(index_tmp);
			x_pos.push_back(x_tmp);
			y_pos.push_back(y_tmp);
		}
		for (int i=0;i<index.size();i++)
		{
			printf("%04d\t%4.8lf\t%4.8lf\n",index[i], x_pos[i], y_pos[i]);
		}
	}
	fclose(pFileRead);
	return 0;
}
/*
C二进制写入
*/
int BinDataWrite_C(){
	double pos[200];
	for (int i=0;i<200;i++)
	{
		pos[i]=i;
	}
	FILE *pFileWriter;
	pFileWriter = fopen("binary.dat","wb");
	if (NULL == pFileWriter)
	{
		printf("写文件出错");
		return -1;
	}
	int mode = 1;
	printf("mode=1:逐个写入\nmode=2:逐行写入");
	scanf("%d",&mode);
	if (1 == mode)
	{
		for (int i=0;i<200;i++)
		{
			for (int i=0;i<200;i++)
			{
				fwrite(&pos[i],sizeof(double),1,pFileWriter);
			}
		}
	}else if (2 == mode)
	{
		fwrite(pos,sizeof(double),200,pFileWriter);
	}
	fclose(pFileWriter);
	return 0;
}
/*
C二进制读取
*/
int BinDataRead_C(){
	FILE *pFileRead;
	pFileRead = fopen("binary.dat","rb");
	if (NULL==pFileRead)
	{
		printf("读取文件出错");
		return -1;
	}
	int mode = 1;
	printf("mode=1:知道有多少数据\nmode=2:不知道有多少数据");
	scanf("%d",&mode);
	if(1==mode){
		double pos[200];
		fread(pos,sizeof(double),200,pFileRead);
		for(int i = 0;i<200;i++){
			printf("%lf\n",pos[i]);
		}
		free(pos);
	}else if (2==mode)
	{
		//获取文件大小
		fseek(pFileRead,0,SEEK_END);
		long lSize = ftell(pFileRead);
		rewind(pFileRead);

		//开辟存储空间
		int num = lSize/sizeof(double);
		double *pos = (double*)malloc(sizeof(double)*num);
		if (NULL ==pos)
		{
			printf("开辟空间出错");
			return -1;
		}
		fread(pos,sizeof(double),num,pFileRead);
		for (int i=0;i<num;i++)
		{
			printf("%lf\n",pos[i]);
		}
		free(pos);
	}
	fclose(pFileRead);
	return 0;
}

/************************************************************************/
/* C++                                                                  */
/************************************************************************/
/*
C++文本写入
*/
int TextWrite_CPP(){
	int index[50];
	double x_pos[50],y_pos[50];
	for (int i=0;i<50;i++)
	{
		index[i]=i;
		x_pos[i]=rand()%1000 * 0.01;
		y_pos[i]=rand()%2000 * 0.01;
	}
	fstream fFileWrite("txt_out_cpp.txt",ios::out);
	if (fFileWrite.bad())
	{
		cout<<"打开文件出错"<<endl;
		return -1;
	}
	for (int i=0;i<50;i++)
	{
		fFileWrite<<setw(5)<<index[i]<<"\t"<<setw(10)<<x_pos[i]<<"\t"<<setw(10)<<y_pos[i]<<endl;
	}
	fFileWrite.close();
	return 0;
}

/*
C++ 读取
*/
int TextRead_CPP(){
	fstream fFileReader;
	fFileReader.open("txt_out_cpp.txt",ios::in);
	//文件打开方式选项：
	//　ios::in　　　　= 0x01,　//供读，文件不存在则创建(ifstream默认的打开方式)
	//　ios::out　　　 = 0x02,　//供写，文件不存在则创建，若文件已存在则清空原内容(ofstream默认的打开方式)
	//　ios::ate　　　 = 0x04,　//文件打开时，指针在文件最后。可改变指针的位置，常和in、out联合使用
	//　ios::app　　　 = 0x08,　//供写，文件不存在则创建，若文件已存在则在原文件内容后写入新的内容，指针位置总在最后
	//　ios::trunc　　 = 0x10,　//在读写前先将文件长度截断为0（默认）
	//　ios::nocreate　= 0x20,　//文件不存在时产生错误，常和in或app联合使用
	//　ios::noreplace = 0x40,　//文件存在时产生错误，常和out联合使用
	//　ios::binary　　= 0x80　 //二进制格式文件
	vector<int> index;
	vector<double> x_pos;
	vector<double> y_pos;
	if (NULL == fFileReader)
	{
		cout<<"打开文件出错"<<endl;
		return -1;
	}
	cout<<"mode=1:按字符读入并输出\nmode=2:按行读取\nmode=3:按数据格式"<<endl;
	int mode = 1;
	cin>>mode;
	if (1==mode)
	{
		char ch;
		while(EOF!=(ch=fFileReader.get())){
			cout<<ch;
		}
	}else if(2 ==mode){
		char line[128];
		int numBytes;
		fFileReader.getline(line,128);
		cout<<line<<"\t"<<endl;
		fFileReader.getline(line,128);
		cout<<line<<"\t"<<endl;
		fFileReader.seekg(0,0);
		while (!fFileReader.eof())
		{
			fFileReader.getline(line,128);
			numBytes = fFileReader.gcount();
			cout<<line<<"\t"<<numBytes<<"字节"<<endl;
		}
	}else if (3==mode)
	{
		int index_tmp =0;
		double x_pos_tmp = 0,y_pos_tmp=0;
		while (!fFileReader.eof())
		{
			fFileReader>>index_tmp>>x_pos_tmp>>y_pos_tmp;
			index.push_back(index_tmp);
			x_pos.push_back(x_pos_tmp);
			y_pos.push_back(y_pos_tmp);
			cout<<index_tmp<<"\t"<<x_pos_tmp<<"\t"<<y_pos_tmp<<endl;
		}
	}
	fFileReader.close();
	return 0;
}
/*
C++二进制写入
*/
int BinDataWrite_CPP(){
	double pos[200];
	for (int i=0;i<200;i++)
	{
		pos[i]=i;
	}
	ofstream fFileWrite("binary.dat",ios::binary);
	if(!fFileWrite)
	{
		cout<<"创建文件失败"<<endl;
		return -1;
	}
	fFileWrite.write((char*)pos,200*sizeof(double));
	fFileWrite.close();
}
/*
C++ 二进制读取
*/
int BinDataRead_CPP(){
	double pos[200];
	ifstream fFileReader("binary.dat",ios::binary);
	if (!fFileReader)
	{
		cout<<"读取文件失败"<<endl;
		return -1;
	}
	fFileReader.read((char*)pos,200*sizeof(double));
	for (int i=0;i<200;i++)
	{
		cout<<pos[i]<<endl;
	}
	fFileReader.close();
	return 0;
}