C++文件流读取

通过运用ofstream和ifstream类去创建对象来进行文件读写。

使用文件流新建或打开一个文件，并写入字符串 "This is a test file".

#include<fstream>
#include<iostream>
using namespace std;
int main()
{
    ofstream outFile("test.txt",ios::out);

    if(!outFile)
        cout<<"Open file or create file error."<<endl;
    else
        outFile<<"This is a file."<<5<<" "<<1.2;
    return 0;
}

使用文件流将创建的文件test.txt.中的所有数据读取出来。

#include<fstream>
#include<iostream>
using namespace std;
int main()
{
    ifstream inFile("test.txt",ios::in);
    int b;
    char a[100];
    float c;

    if(!inFile)
        cout<<"File open error."<<endl;
    else
    {
        inFile>>a;
        in
        cout<<"string--"<<a<<endl;
        cout<<"int--"<<b<<endl;
        cout<<"float--"<<c<<endl;
    }
    return 0;
}

使用ifstream类成员函数seekg，结合文件输入输出流，写的一个wav文件解析的应用。

wav文件解析：

#include<fstream>
#include<iostream>
#include<cstring>
//#incl
#define MAX_STR_LEN 32
using namespace std;
class wav
{
    public:
             char id[4];
    unsigned long file_size;
      //文件大小
    unsigned short channel;            //通道数
    unsigned int frequency;        //采样频率
    unsigned long Bps;                //Byte率
    unsigned short sample_num_bit;    //一个样本的位数
    unsigned long data_size;        //数据大小
    unsigned char *data;            //音频数据 ,这里要定义什么就看样本位数了，我这里只是单纯的复制数据
};
int main()
{
    wav ww;

    ifstream inFile("do.wav",ios::in|ios::binary);
    if(!inFile)
        cout<<"error";
    else{
    char buff[4];
    unsigned long tlong ;
    unsigned short tshort;

    inFile.seekg(0,ios::beg);
    inFile>>ww.id;

    inFile.seekg(12,ios::beg);
    inFile>>buff;
    cout<<"fmt:"<<buff<<endl;

    inFile.seekg(16,ios::beg);
    inFile>>buff;
    memcpy(&tlong,buff,sizeof(unsigned long));
    cout<<"fmt size:"<<tlong<<endl;

    inFile.seekg(20,ios::beg);
    inFile>>buff;
    memcpy(&tshort,buff,sizeof(unsigned short));
    cout<<"format:"<<tshort<<endl;

    inFile.seekg(4,ios::beg);
    inFile>>ww.file_size;
    inFile.seekg(22,ios::beg);
    inFile>>ww.channel;
    inFile.seekg(24,ios::beg);
    cout<<ww.id<<endl<<ww.file_size<<endl<<ww.channel<<endl<<ww.frequency;
    }
    return 0;
}