C++ 文件復制

#include<iostream>
#include<fstream>

void copy(char* src, char* dst);
int main()
{
    using namespace std;
    char src[50] = "E:/test/jdk-8u121-windows-x64.exe";
    char dst[50] = "E:\\test\\jdk-8u121-windows-x64_bak.exe";
    copy(src, dst);
    
    return 0;
}

void copy(char* src, char* dst)
{
    using namespace std;
    ifstream in(src,ios::binary);
    ofstream out(dst,ios::binary);
    if (!in.is_open()) {
        cout << "error open file " << src << endl;
        exit(EXIT_FAILURE);
    }
    if (!out.is_open()) {
        cout << "error open file " << dst << endl;
        exit(EXIT_FAILURE);
    }
    if (src == dst) {
        cout << "the src file can't be same with dst file" << endl;
        exit(EXIT_FAILURE);
    }
    char buf[2048];
    long long totalBytes = 0;
    while(in)
    {
        //read從in流中讀取2048字節，放入buf數組中，同時文件指針向后移動2048字節
        //若不足2048字節遇到文件結尾，則以實際提取字節讀取。
        in.read(buf, 2048);    
        //gcount()用來提取讀取的字節數，write將buf中的內容寫入out流。
        out.write(buf, in.gcount());    
        totalBytes += in.gcount();
    }
    in.close();
    out.close();
}