I have a cpp file which contains of:
#include <QApplication>
int/**/ main(int /*c*/,char**v)
{/*
*/
QApplication app(c,v);//
//
return app.exec();
/**/
}
I'm opening this file:
boost::filesystem3::path file("C:\\Users\\Art\\Desktop\\six_lines.txt");
boost::filesystem3::ifstream fin(file);
if (fin)
{
std::string read_line;
while (getline(fin,read_line))//here I'd hope to read just one line
{
}
}
Unfortunately getline(fin,read_line) is executed just once (file exists). Why?
Related
I have one csv file in which 3 column and 866300 lines. I have try to write this data into other csv file. when i try to write it has write 866248 lines in file after that remaining 52 lines are not write in file. what is the problem I do not understand it. I have try to debug this problem using print that data on console then it has print till last line on the console. only the problem in write the data in file.
#include <QCoreApplication>
#include <QFile>
#include <QStringList>
#include <QDebug>
#include <QTextStream>
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QFile file("C:/Users/hello/Downloads/hello.csv");
QFile write("new_data.csv");
if(!file.open(QIODevice::ReadOnly | QIODevice::Text))
{
qDebug()<<file.errorString();
return 1;
}
if(!write.open(QIODevice::WriteOnly |QIODevice::Append))
{
qDebug()<<file.errorString();
return 1;
}
QTextStream out(&write);
QStringList data;
while (!file.atEnd())
{
QString line = file.readLine();
data = line.split(',');
if (data[0]=="v1")
{
out<<line;
continue;
}
else
{
int seq = (data[0].toInt())-1;
QString str = QString::number(seq)+","+data[1]+","+data[2].trimmed();
qDebug()<<str;
out<<str<<"\n";
}
}
return a.exec();
}
please help.
Please close the file before the return a.exec(); this line and after the while loop. add this line below line.
write.close();
First of all, this is NOT my own code! It's taken from Google's Android sourcecode https://android.googlesource.com/platform/art/+/android-9.0.0_r10/tools/hiddenapi/hiddenapi.cc
So, it should be tested and should work! But, it fails at the point "insert..."
Short code:
/*...*/
std::unordered_set<std::string> light_greylist_;
/*...*/
/*Caller:*/ OpenApiFile(light_greylist_path_, &light_greylist_);
bool OpenApiFile(const std::string& path, std::unordered_set<std::string>* list) {
std::ifstream api_file(path, std::ifstream::in);
for (std::string line; std::getline(api_file, line);) {
/* line IS filled; I've checked it with a simple fprintf(): [this IS my code for testing]*/
FILE *stream = fopen("test.txt", "a+");
fprintf(stream, "%s\n", line.c_str());
fclose(stream);
/* This is the point where it crashes with an "Illegal instruction (core dumped)"*/
list->insert(line);
}
api_file.close();
return true;
}
What goes wrong?
I'd make list a reference instead of a pointer. It's hard to say why the original code uses pointers since it'll most probably crash if called with NULL. Also check that the file has been successfully opened (even though it seems to have succeeded for you this time).
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <unordered_set>
bool OpenApiFile(const std::string& path, std::unordered_set<std::string>& list) {
std::ifstream api_file(path, std::ifstream::in);
if (!api_file) {
return false;
}
for (std::string line; std::getline(api_file, line);) {
list.insert(line);
}
return true;
}
int main(int argc, char* argv[]) {
std::vector<std::string> files(argv+1, argv+argc);
for(auto& light_greylist_path_ : files) {
std::unordered_set<std::string> light_greylist_;
if (OpenApiFile(light_greylist_path_, light_greylist_) == false) {
std::cerr << "failed opening "+light_greylist_path_+"\n";
} else {
for(auto& lg : light_greylist_) {
std::cout << lg << "\n";
}
}
}
return 0;
}
I'm having this error in my Qt Application:
Debug Error!
Program: C:\Qt\Qt5.1.1\5.1.1\msvc2012_64\bin\QtCored.dll
Module: 5.1.1 File: global\qglobal.cpp
Line: 2014
ASSERT: "allArguments.size() == origArgc" in file
kernel\qcoreapplication.cpp, line 2095
#include <QCoreApplication>
#include <QDebug>
#include <QStringList>
int main(int argc, char *argv[])
{
QCoreApplication app(argc,argv);
qDebug()<<"argc:" << argc;
qDebug()<<"arguments:"<<app.arguments().length();
return 0;
}
Why is that so?
The issue was that I was passing arguments with a new line character in it.
After I removed, it worked again.
How do I copy a file from one folder to another folder using C++?
This should be the minimal code required:
#include <fstream>
// copy in binary mode
bool copyFile(const char *SRC, const char* DEST)
{
std::ifstream src(SRC, std::ios::binary);
std::ofstream dest(DEST, std::ios::binary);
dest << src.rdbuf();
return src && dest;
}
int main(int argc, char *argv[])
{
return copyFile(argv[1], argv[2]) ? 0 : 1;
}
it glosses around some potentially complicated issues: error handling, filename character encodings... but could give you a start.
With std::filesystem::copy_file from C++17:
#include <exception>
#include <filesystem>
#include <iostream>
namespace fs = std::filesystem;
int main()
{
fs::path sourceFile = "path/to/sourceFile.ext";
fs::path targetParent = "path/to/target";
auto target = targetParent / sourceFile.filename(); // sourceFile.filename() returns "sourceFile.ext".
try // If you want to avoid exception handling, then use the error code overload of the following functions.
{
fs::create_directories(targetParent); // Recursively create target directory if not existing.
fs::copy_file(sourceFile, target, fs::copy_options::overwrite_existing);
}
catch (std::exception& e) // Not using fs::filesystem_error since std::bad_alloc can throw too.
{
std::cout << e.what();
}
}
I've used std::filesystem::path::filename to retrieve the source filename without having to type it manually. However, with std::filesystem::copy you can omit passing the filename to the target path at all:
fs::copy(sourceFile, targetParent, fs::copy_options::overwrite_existing);
Change the behaviour of both functions with std::filesystem::copy_options.
If you're willing to use the Boost C++ libraries, take a look at filesystem::copy_file().
Here's a previous question covering copy_file():
How to use copy_file in boost::filesystem?
This is how you can do this.
include c++ library <windows.h>
Use function
CopyFile("d:/folder1/file.exe","d:/folder2/file.exe",true)
All Done :)
The code below will copy all the file from one directory to another.
Its working code in C++
#include <windows.h>
/*
BOOL Copy(char r_szPath[1024], char r_szDir[1024])
{
char l_szTemp[2048] = {0};
sprintf(l_szTemp,"%s\%s"r_szPath,r_szDir);
if(IsDirectory(
}*/
#include <stdio.h>
#include<conio.h>
BOOL __Copy(char r_szSrcPath[1024],char r_szDesPath[1024])
{
WIN32_FIND_DATA FindFileData;
HANDLE hFind;
char l_szTmp[1025] = {0};
memcpy(l_szTmp,r_szSrcPath,1024);
char l_szSrcPath[1025] = {0};
char l_szDesPath[1025] = {0};
memcpy(l_szSrcPath,r_szSrcPath,1024);
memcpy(l_szDesPath,r_szDesPath,1024);
char l_szNewSrcPath[1025] = {0};
char l_szNewDesPath[1025] = {0};
strcat(l_szTmp,"*");
hFind = FindFirstFile(l_szTmp, &FindFileData);
if(hFind == NULL) return FALSE;
do
{
if(FindFileData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
{
if(strcmp(FindFileData.cFileName,"."))
{
if(strcmp(FindFileData.cFileName,".."))
{
printf ("The Directory found is %s<BR>, FindFileData.cFileName);
sprintf(l_szNewDesPath,"%s%s\",l_szDesPath,FindFileData.cFileName);
sprintf(l_szNewSrcPath,"%s%s\",l_szSrcPath,FindFileData.cFileName);
CreateDirectory(l_szNewDesPath,NULL);
__Copy(l_szNewSrcPath,l_szNewDesPath);
}
}
}
else
{
printf ("The File found is %s<BR>, FindFileData.cFileName);
char l_szSrcFile[1025] = {0};
char l_szDesFile[1025] = {0};
sprintf(l_szDesFile,"%s%s",l_szDesPath,FindFileData.cFileName);
sprintf(l_szSrcFile,"%s%s",l_szSrcPath,FindFileData.cFileName);
BOOL l_bRet = CopyFile(l_szSrcFile,l_szDesFile,TRUE);
}
}
while(FindNextFile(hFind, &FindFileData));
FindClose(hFind);
return TRUE;
}
int main(int argc, char *argv[])
{
__Copy("C:\fcdb\","E:\sandy\");
getch();
return 0;
}
How do I copy a file from one folder to another folder using C++?
This should be the minimal code required:
#include <fstream>
// copy in binary mode
bool copyFile(const char *SRC, const char* DEST)
{
std::ifstream src(SRC, std::ios::binary);
std::ofstream dest(DEST, std::ios::binary);
dest << src.rdbuf();
return src && dest;
}
int main(int argc, char *argv[])
{
return copyFile(argv[1], argv[2]) ? 0 : 1;
}
it glosses around some potentially complicated issues: error handling, filename character encodings... but could give you a start.
With std::filesystem::copy_file from C++17:
#include <exception>
#include <filesystem>
#include <iostream>
namespace fs = std::filesystem;
int main()
{
fs::path sourceFile = "path/to/sourceFile.ext";
fs::path targetParent = "path/to/target";
auto target = targetParent / sourceFile.filename(); // sourceFile.filename() returns "sourceFile.ext".
try // If you want to avoid exception handling, then use the error code overload of the following functions.
{
fs::create_directories(targetParent); // Recursively create target directory if not existing.
fs::copy_file(sourceFile, target, fs::copy_options::overwrite_existing);
}
catch (std::exception& e) // Not using fs::filesystem_error since std::bad_alloc can throw too.
{
std::cout << e.what();
}
}
I've used std::filesystem::path::filename to retrieve the source filename without having to type it manually. However, with std::filesystem::copy you can omit passing the filename to the target path at all:
fs::copy(sourceFile, targetParent, fs::copy_options::overwrite_existing);
Change the behaviour of both functions with std::filesystem::copy_options.
If you're willing to use the Boost C++ libraries, take a look at filesystem::copy_file().
Here's a previous question covering copy_file():
How to use copy_file in boost::filesystem?
This is how you can do this.
include c++ library <windows.h>
Use function
CopyFile("d:/folder1/file.exe","d:/folder2/file.exe",true)
All Done :)
The code below will copy all the file from one directory to another.
Its working code in C++
#include <windows.h>
/*
BOOL Copy(char r_szPath[1024], char r_szDir[1024])
{
char l_szTemp[2048] = {0};
sprintf(l_szTemp,"%s\%s"r_szPath,r_szDir);
if(IsDirectory(
}*/
#include <stdio.h>
#include<conio.h>
BOOL __Copy(char r_szSrcPath[1024],char r_szDesPath[1024])
{
WIN32_FIND_DATA FindFileData;
HANDLE hFind;
char l_szTmp[1025] = {0};
memcpy(l_szTmp,r_szSrcPath,1024);
char l_szSrcPath[1025] = {0};
char l_szDesPath[1025] = {0};
memcpy(l_szSrcPath,r_szSrcPath,1024);
memcpy(l_szDesPath,r_szDesPath,1024);
char l_szNewSrcPath[1025] = {0};
char l_szNewDesPath[1025] = {0};
strcat(l_szTmp,"*");
hFind = FindFirstFile(l_szTmp, &FindFileData);
if(hFind == NULL) return FALSE;
do
{
if(FindFileData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
{
if(strcmp(FindFileData.cFileName,"."))
{
if(strcmp(FindFileData.cFileName,".."))
{
printf ("The Directory found is %s<BR>, FindFileData.cFileName);
sprintf(l_szNewDesPath,"%s%s\",l_szDesPath,FindFileData.cFileName);
sprintf(l_szNewSrcPath,"%s%s\",l_szSrcPath,FindFileData.cFileName);
CreateDirectory(l_szNewDesPath,NULL);
__Copy(l_szNewSrcPath,l_szNewDesPath);
}
}
}
else
{
printf ("The File found is %s<BR>, FindFileData.cFileName);
char l_szSrcFile[1025] = {0};
char l_szDesFile[1025] = {0};
sprintf(l_szDesFile,"%s%s",l_szDesPath,FindFileData.cFileName);
sprintf(l_szSrcFile,"%s%s",l_szSrcPath,FindFileData.cFileName);
BOOL l_bRet = CopyFile(l_szSrcFile,l_szDesFile,TRUE);
}
}
while(FindNextFile(hFind, &FindFileData));
FindClose(hFind);
return TRUE;
}
int main(int argc, char *argv[])
{
__Copy("C:\fcdb\","E:\sandy\");
getch();
return 0;
}