Question

以下是我必须进行更改的文件（as-1.txt）。应该as-1而不是as-2。

此代码生成as-1.txt的副本，并且还更改该文件的内部数据。如果文件中的文件名为as-2，则as-1也应更改为as-2。

我已完成复制部分但无法更改文件数据：

示例输入：

&cntrl
      pTopt = 298.15, pdens = 0.997, prcut = 12.0, pion = t,
      pihot = t, prQM = 5.5, prSM = 5.3, prQI=3.0, piguess = f,
      pinit = t, pnstep = 5000, pnscale = 100,
      pnstat = 5, pnout = 5, pnrst = 5,  pioutc = t, pioutv = t, pnoutc = 5, pnoutv = 5,
      msolute = t, nosa = 1,  pichrg = t
    gfileOut =   'as-1.out',
      gfileEnout = 'as-1.en',
      gfileInfo =  'as-1.info',
      gfileStart = 'init.in',
      gfileRst =   'as-1.rst',
      gfileTraj =  'as-1.traj',
      gfileVeloc = 'as-1.vel',
      gfileQmen =  'as-1.qmen'
     &end

我的代码：

#include "stdafx.h"
#include "iostream"
#include "fstream"
#include "windows.h"
#include "stdio.h"
#include "string"
using namespace std;
void main()
{

        string str;   
        ifstream myfile("as-1.txt");// for reading a file
        char j = '2';

        if (!myfile)// if file not present 
        {
            cerr << "file not opening";//cerr is for displaying errors
            exit(1);
        }

        for (int i = 0; i < 9; i++)// for multiple copies
        {

        char name[9] = { 'a', 's', '-', j,'.','t','x','t' ,'\0'};// for setting file name , j increments 
        ofstream myfile1(name);// to write on file
        cout << name<<endl;

        while (!myfile.eof())// run till end of file
        {
            getline(myfile,str);    // get line by line text from myfile
            myfile1 << str << endl;// insert line fetched from myfile to myfile 1
        }
        j++;// to increment in ascii code
        myfile.clear();// to clear end of file(eof)
        myfile.seekg(0, ios::beg);//take cursor to begining of file

        }

       system("pause");
}

Answer 1

要替换您，可以使用std::string的{{3}}方法，但您需要知道要替换的字符范围（找到它使用find方法）。我在这个replace找到了很好的方法。另外最好使用std::string并且不要将其与char和char数组混淆，因此要将int转换为std::string我使用了另一个as-10.txt 3}}，或者你可以简单地使用answer，如果你可以接受的话。

所以这里是完整代码，它将创建9个新文件as-2.txt，as-3.txt，as-4.txt，as-5.txt，as-6.txt，as-7.txt ，as-8.txt，as-9.txt和#include <iostream> #include <fstream> #include <string> #include <sstream> namespace patch { template< typename T > std::string to_string( const T& n ) { std::ostringstream stm; stm << n; return stm.str(); } } using namespace std; void replace_all(string& str, const string& from, const string& to) { if(from.empty()) return; size_t start_pos = 0; while((start_pos = str.find(from, start_pos)) != string::npos) { str.replace(start_pos, from.length(), to); start_pos += to.length(); } } int main(int argc, char** argv) { ifstream myfile("as-1.txt"); if(!myfile) { cerr << "Could not open file " << "as-1.txt\n"; return 1; } for(int i = 0; i < 9; i++) { string name = "as-" + patch::to_string(i + 2) + ".txt"; ofstream myfile1(name.c_str()); if(!myfile1) { cerr << "Could not open file " << name << "\n"; return 1; } cout << name<<endl; string line; while(!myfile.eof()) { getline(myfile, line); replace_all(line, "as-1", "as-" + patch::to_string(i + 2)); myfile1 << line << endl; } myfile.clear(); myfile.seekg(0, ios::beg); } return 0; }。

NSURLConnection

在c ++中复制文件10次并编辑它们

1 个答案: