I've been trying to take a .txt document with three number entries, read those entries as strings and convert those entries in ints, then put them into an int array, but had no success in doing so and i have no clue as to why. Note that the entries as well as some variable names are pre determined by the assignment, additionally we have to use the std::stoi("string") command, which i am not familiar with nor has any syntax been provided to us (which is especially strange since we are usually not allowed to stray to far from the lecture material)
What I excpected to happen is that the numbers from the .txt file were converted into an array, however what actually happened is that an "unhandled exception" (my apologies if that term does not make sanes we have to programm in our native language) occured and the string library opened itself, marking the error on line 107. The problematic line in my code seems to be "auftraegearray[i++] = std::stoi(MengeanAuftraegen);"
int main()
{
std::fstream Auftraege;
Auftraege.open("Auftraege37.txt", std::ios::out);
Auftraege << "10" << std::endl;
Auftraege << "1" << std::endl;
Auftraege << "20" << std::endl;
Auftraege.close();
int i = 0;
int auftraegearray[4];
std::string MengeanAuftraegen;
Auftraege.open("Auftraege37.txt", std::ios::in);
while (!Auftraege.eof())
{
getline(Auftraege, MengeanAuftraegen);
std::cout << MengeanAuftraegen << std::endl;
auftraegearray[i++] = std::stoi(MengeanAuftraegen);
}
Auftraege.close();
Related
I'm trying to parse C++ code with ANTLR4 with a parser in Python3. I have a code line below,
std::stringstream str;
str << "A" << "B" << "C" << "D";
I have a visitor function for every visitShiftexpression, and inside it I can get the whole line str << "A" << "B" << "C" << "D";, I want to be able to loop through each of those << and get each of them one by one.
Can anyone please let me know how I can do that?
Thanks
I updated to the latest version of C++ grammar and I got std::vector for the operators and by iterating over the std::vector i managed to get what i needed.
I'm quite new to C++, but I'm used to some coding with R language. I started, a few weeks ago, to put together a small application that should copy and rename file pairs (.seq/.ab1). Result from a DNA sequencer analysis (renaming hundreds of them manually would be a real time waste, specially because we have lists with their new names).
Everything seemed to be fine, but the new files (those copied) appear with a "special character" in their names (right before the file type), it seeems like a space, but its not (I've replaced it with a space, and the file opened correctly). After deleting it the file can be oppened by its associated application, but with it, the aplication acusses the file to be corrupted.
The issue seems to come from the code related to ostringstream::str member function, but I honestly don't know how to fix it. I wonder if its not inserting a null character there, before I append the file type...
Here is the part of the code responsible. It gets the old and new names from a 2 column csv file, data separated by ";". Original data, and new (renamed files) data are kept in diferent directories, thats the reason I need to create a string with each file path inside a for loop. I intend to check old and new files content later, probably with memcmp. But first I need them to be correctly renamed.
I'm on a Ubuntu 14.04 (64 bit) machine with gcc 4.8.4 as compiler. I already excuse myself for the probably poor coding and bad english, I'm not a native speaker (writer, actually).
fNew.open(filename);
std::ostringstream oldSeqName (std::ostringstream::ate);
std::ostringstream newSeqName (std::ostringstream::ate);
std::ostringstream oldAb1Name (std::ostringstream::ate);
std::ostringstream newAb1Name (std::ostringstream::ate);
std::fstream log;
time_t now = time(0);
for (std::string nOld, nNew; getline(fNew, nOld, ';') && getline(fNew, nNew); )
{
std::cout << "Old Name: " << nOld << " -> New Name: " << nNew << std::endl;
// Keep a log of the name changes
log.open("NameChangesLog.txt", std::fstream::out | std::fstream::app);
log << ctime(&now) << " - " << "Old Name: " << nOld << " -> New Name: " << nNew << std::endl;
log.close();
// Create old seq files paths string
oldSeqName.str(nOld);
oldSeqName << ".seq";
std::string osn = "./Seq/" + oldSeqName.str();
// Create new seq files paths string
newSeqName.str(nNew);
newSeqName << ".seq";
std::string nsn = "./renamed/" + newSeqName.str();
std::ifstream ifseq(osn, std::ios::binary);
std::ofstream ofseq(nsn, std::ios::binary);
ofseq << ifseq.rdbuf();
ifseq.close();
ofseq.close();
// Create old ab1 files paths string
oldAb1Name.str(nOld);
oldAb1Name << ".ab1";
std::string oan = "./Seq/" + oldAb1Name.str();
// Create new abq files paths string
newAb1Name.str(nNew);
newAb1Name << ".ab1";
std::string nan = "./renamed/" + newAb1Name.str();
std::ifstream ifab1(oan, std::ios::binary);
std::ofstream ofab1(nan, std::ios::binary);
ofab1 << ifab1.rdbuf();
ifab1.close();
ofab1.close();
}
fNew.close();
Is the list file prepared on Windows machine? In that case it would have DOS line ending (\r\n) and is not well suited for getline on Unix. The character you see is likely \r. Make sure you use dos2unix utility before feeding the list file to your program
You probably forget to trim the values returned from getline, so they may still contain whitespace. Whitespace may be tricky to pick up by the application.
I am working on a money program. Currently I am trying to make a part in the program that displays a list that shows every transaction that was made in the session. My problem is that when I convert the money amount to a string instead of displaying something like 100.35 in when converted to a string it instead displays something like 100.35000000. I was wondering if there was any way I could make the program drop the additional zeros? Here is a sample of how I convert the numbers to a string
int main(){
double samplemoney=100.35;
string sample="Today we made $";
string comsample;
comsample=sample+std::tostring(money)+".";
cout<<comsample<<endl;
return 0;
}
In my main program this part is handled with a class but as I said earlier it seems like no matter what the money value I put in is it will display a series of zero and I want my program to drop the unnecessary zeros.
Let's say you have this number:
double number = 190.0391000;
If the problem is displaying the value you may use
std::cout << std::setprecision(5) << number
where f is the number you want to show.
If your problem is having a string with a finite precision you can use sprintf() in the following way:
char arr[128];
sprintf(arr,"%3.2f", number);
std::string formattedstring(arr);
or in a more C++ oriented way something like this
std::stringstream strn;
strn.precision(2);
strn << std::fixed << number;
and then you get the string in the following way:
std::string formattedstring = strn.str();
I attach the full text of program here... tested on my machine:
#include <sstream>
#include <iostream>
int main() {
float number=100.24324232;
std::stringstream strn;
strn.precision(2);
strn << std::fixed << number;
std::cout << strn.str() << "\n";
return( 0 );
}
I have a function in my program that outputs a data structure that consists of three doubles in two formats, one text and one binary.
When I run the program in debug and release modes, I end up with different binary outputs but identical text outputs. What is going on?
Here is the binary output code:
void outputPoints(xyz* points, string description, int length, param parameters)
{
stringstream index;
index.str("");
index << setw( 3 ) << setfill( '0' ) << parameters.stage;
string outputName = parameters.baseFileName + " " + index.str() + " " + description + ".bin"; // create file name
ofstream output; // create output object
cout << "Output " << outputName.c_str() << "...";
output.open(outputName.c_str(), std::ios::binary | std::ios::out); // open or create file for output
output.write(reinterpret_cast<char*>(points), (sizeof(xyz) * length));
output.close(); // close output object
cout << "done" << endl;
}
The debug build usually initializes variables with some patterns. Usually data allocated has the content CDCD, deleted objects are overwritten with FEEE. The CDCD pattern is overwritten when you initialize your variables. The release build doesn't initiliaze with these patterns.
It's worth to check your program for uninitialized variables. You can define a Dump function that just prints the (fist few bytes of) the suspected variables.
I don't know whether you got a solution for your issue and I did not look at your code.
I had the same issue because I was adding unsigned char and unsigned short and saving into unsigned short. I changed all variables to unsigned short and the issue was solved.
I have code such as this. I use
pvalueholder is class that is polymorphic , it can hold all sort of types, string..etc..
It also can have a type undefined.
typedef hash_map<pvalueholder,pvalueholder,pvaluehasher > hashtype;
hashtype h;
pvalueholder v;
v="c";
h[v]=5; // h has one element
pvalueholder v2=h[v]; // here h gets a new key/value how is that possible?
cout << (string) (h[v]) << endl; // here h gets another new key/value how is that possible?
int i =0;
for (hashtype::iterator h1=h.begin(); h1!=h.end();h1++)
{
cout << "no: " << i++ << endl;
} // this prints three lines, it should print one...
Two values are undefined here, the third one is 5 as expected.
size_t pvaluehasher::operator() (const pvalueholder& p) const
{
cout << "hashvalue:" << p.value->hashvalue() << endl;
return p.value->hashvalue();
}
returns
Here is what is printed:
hashvalue:84696444
hashvalue:84696444
hashvalue:84696444
returns:1
hashvalue:84696444
returns:1
hashvalue:84696444
returns:1
returns:1
hashvalue:84696444
Do you have any ideas what it may be?
Thank you.
Solution:
the function operator()(parameter1,parameter2) needs to be different in case of Microsoft STL.
For microsoft, it needs to return less than relationship between parameter1 and parameter2.
For gcc, it needs to return equality. I returned equality.
The comparison function for the keys was not correct...
The function returned true for equality while it has to return less than in case of Microsoft STL.
My guess would be that your hash function is incorrect - meaning it produces different hash values given the same key "c".
Show the declaration for pvalueholder and full code for pvaluehasher.
It's almost impossible to comment on hash_map, because it's never been standardized, and the existing implementations aren't entirely consistent. Worse, your code doesn't seem to be correct or compilable as it stands -- some places the value associated with the key seems to be an int, and other places a string.
Using std::tr1::unordered_map and fixing the rest of the code to compile and seem reasonable, like this:
#include <unordered_map>
#include <iostream>
#include <string>
using namespace std;
typedef std::tr1::unordered_map<std::string, int> hashtype;
std::ostream &operator<<(std::ostream &os, std::pair<std::string, int> const &d) {
return os << d.first << ": " << d.second;
}
int main() {
hashtype h;
std::string v = "c";
h[v]=5; // h has one element
int v2=h[v];
cout << h[v] << endl;
int i =0;
for (hashtype::iterator h1=h.begin(); h1!=h.end();h1++)
{
cout << *h1 << endl;
} // this prints three lines, it should print one...
return 0;
}
The output I get is:
5
c: 5
This seems quite reasonable -- we've inserted only one item, as expected.
Solution: the function operator()(parameter1,parameter2) needs to be different in case of Microsoft STL. For microsoft, it needs to return less than relationship between parameter1 and parameter2. For gcc, it needs to return equality. I returned equality. The comparison function for the keys was not correct... The function returned true for equality while it has to return less than in case of Microsoft STL.