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[英]Write to ofstream followed by read with ifstream doesn't read entire file
[英]Read from file (ifstream) and write to file (ofstream) - problems with encoding
注意:我是C ++新手。
我有以下问题:
我从文件中读取内容,并希望将字符串部分替换为其他字符串部分。 简单的任务,应该很容易做到。 我用setmode做了一些实验,但是没有成功。 我还用谷歌搜索,但也没有帮助我。
可能存在一些小代码问题,但请着重解决该问题。 转换测试数据如下:
int main(int argc, char** argv) {
stringstream strs;
//Choose output file
ofstream ofile;
string filename;
cout << "Ausgabepfad eingeben" << endl;
cin >> filename;
ofile.open(&filename[0]);
//Choose input file
ifstream ifile;
cout << "Quellpfad eingeben" << endl;
cin >> filename;
ifile.open(&filename[0]);
//Choose decoding - doesnt work, I know - That was for experiments
int mode = 0;
cout << "Decoding wählen\n1 für _O_TEXT\n2 für _O_BINARY\n3 für _O_U16TEXT\n4 für _O_U8TEXT\n5 für _O_WTEXT" << endl;
cin >> mode;
/* switch(mode){
case 1:
_setmode (_fileno(ifstream), _O_TEXT);
break;
case 2:
_setmode (_fileno(ifstream), _O_BINARY);
break;
case 3:
_setmode (_fileno(ifstream), _O_U16TEXT);
break;
case 4:
_setmode (_fileno(ifstream), _O_U8TEXT);
break;
case 5:
_setmode (_fileno(ifstream), _O_WTEXT);
break;
default:
cerr << "ungültige Codierung gewählt"
}
*/
//Choose search string and replacement string
ifile.seekg(0); //not necessary, I know
string searchstr = "";
cout << "Suchstring eingeben" << endl;
cin >> searchstr;
string fillstr;
cout << "Ersetzungsstring eingeben" << endl;
cin >> fillstr;
cout << fillstr;
int marker = 0;
if(searchstr.length()<1){
return 0;
}
//actual program
while(!ifile.eof()){
int counter = 0;
ifile.seekg(marker);
char current = ifile.get();
if(current==searchstr[0]){ //if the first search letter matches, seet, if the others do.
marker++;
counter++;
for(int i = 1; i < searchstr.length(); i++){
ifile.seekg(marker);
if(ifile.get()==searchstr[i]){
counter++;
marker++;
}else{
marker-i;
break;
}
}
if(counter == searchstr.length()){
ofile << fillstr;
cout << endl;
}
}else{
ofile << ifile.get();
cout << ifile.get();
}
marker++;
}
ifile.close();
ofile.close();
cout << endl;
return 1;
}
以下字符串
|-
应该替换为
\n
文本(示例)为:
|[[Allgemeines Deutsches Kommersbuch:1|1]]
|1
|[[Abend wird's, des Tages (Körner)]]
|[[Die Eichen (Körner)]]
|-
|[[Allgemeines Deutsches Kommersbuch:2|2]]
|2
该程序运行,但是不起作用。 输出的数字很多,毫无意义。
输出的数字很多,毫无意义。
调用ifile.get()
返回一个int_type
类型的值。 因此<<
输出所有这些整数值。
更换
ofile << ifile.get();
(做格式化的整数输出)
ofile << char( ifile.get() );
或(首选,使用未格式化的输入和输出)
ofile.put( ifile.get() );
用标准流,迭代器和算法来表达问题几乎总是一个更好的主意:
#include <iostream>
#include <string>
#include <sstream>
#include <algorithm>
// lets get the logic right in terms of streams
void replace_all(std::ostream& dest, std::istream& source,
const std::string& search_for, const std::string& replace_with)
{
std::string line;
while (std::getline(source, line)) {
auto ipos = line.begin();
while (ipos != line.end())
{
ipos = std::search(ipos, line.end(), search_for.begin(),
search_for.end());
if (ipos != line.end())
{
auto start_index = std::distance(line.begin(), ipos);
line.replace(ipos, std::next(ipos, search_for.length()),
replace_with);
ipos = std::next(line.begin() + start_index + replace_with.length());
}
}
dest.write(line.data(), line.size());
dest.put('\n');
}
}
// now test
int main()
{
std::string search_for = "|-";
std::string replace_with = "";
std::istringstream source_stream("|[[Allgemeines Deutsches Kommersbuch:1|1]]\n"
"|1\n"
"|[[Abend wird's, des Tages (Körner)]]\n"
"|[[Die Eichen (Körner)]]\n"
"|-\n"
"|[[Allgemeines Deutsches Kommersbuch:2|2]]\n"
"|2\n");
std::ostringstream dest_stream;
replace_all(dest_stream, source_stream, search_for, replace_with);
std::cout << dest_stream.str();
return 0;
}
// todo: write a new main which asks for filenames, builds ifstreams and ofstreams, and calls replace_all()
预期输出:
|[[Allgemeines Deutsches Kommersbuch:2|2]]
|2
Jewels-MacBook-Pro:play richardh$ ./replace.cpp
|[[Allgemeines Deutsches Kommersbuch:1|1]]
|1
|[[Abend wird's, des Tages (Körner)]]
|[[Die Eichen (Körner)]]
|[[Allgemeines Deutsches Kommersbuch:2|2]]
|2
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