C++文件读写

C++文件读写实例（BinWriter）

从源文件中读取指定位置的一段数据写入到目的文件的指定位置

#include <iostream>#include <fstream>using namespace std;int main(int n,char** args){    if(n<6){        cout<<"Usage: BinWriter src_filename read_offset size  des_filename write_offset";        exit(0);    }    char *src_filename=args[1];    long read_offset=atol(args[2]);//偏移量    int bufsize=atoi(args[3]);    char *des_filename=args[4];    long write_offset=atol(args[5]);//偏移量    FILE *fp_read=fopen(src_filename,"rb+");    FILE *fp_write=fopen(des_filename,"rb+");    if(fp_read==NULL){        cout<<"ERROR:fail to open source file！";        exit(0);    }    if(fp_write==NULL){        cout<<"ERROR:fail to open destination file!";        exit(0);    }    //read source file to buf    char *buf=new char[bufsize];    int read_fromwhere=0;//偏移基址    fseek(fp_read,read_offset,read_fromwhere);    fread(buf,sizeof(char),bufsize,fp_read);    //write buf to destination file    int write_fromwhere=0;//偏移基址    fseek(fp_write,write_offset,write_fromwhere);    fwrite(buf,sizeof(char),bufsize,fp_write);    cout<<"written success!";    fclose(fp_read);    fclose(fp_write);    delete buf;    return 0;}