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Please find the code sample
void createFile(const std::string& FileName, const std::string& Content)
{
ofstream of(FileName.c_str());
of<<Content;
of.close();
}
const std::string testFile = "/etc/testFile";
const std::string EmptyContent = "";
createFile(testFile, EmptyContent);
File is not creating at /etc/ directory. I think this is related to permissions. What extra I have to add in the code to work.
There's nothing extra that you can add to this program to "make it work". If an arbitrary program can write to /etc, this would toss the traditional POSIX security model out the window.
In order to be able to write to /etc, your program must be executed as root.
It seems to be a permission issue. Try to run your program using sudo:
sudo yourprogram
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Im trying to create all folder in a path that reach to a file, for that by a little search I found out about std::filesystem::create_directories its ok but the problem of using it is looks like its can't handle long paths with so many subfolders, for small path its working without any problem, but when I tested it with a path that have 14 subfolder and near 185 character it failed and give me the The filename or extension is too long. error
here is the code Im using so far:
void create_dirs(std::filesystem::path path)
{
if (!std::filesystem::exists(path))
{
path.remove_filename(); // remove file name
try
{
std::filesystem::create_directories(path); // create dirs
}
catch (std::filesystem::filesystem_error& e)
{
std::cerr << e.what() << std::endl;
}
}
}
so what can I do for this? and what is the best solution?
My OS: Windows
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I tried using std::filesystem::space(dir) but with no luck -> it cannot determine available disk space, sets it to uintmax.
auto info = std::filesystem::space("K:\\Dir");
if(info.available == static_cast<uintmax_t>(-1))
{
std::cout << "Error occurred!\n";
}
K:\Dir does indeed exist. And this snippet prints Error occurred for my drive mounted on K:.
If you want to get the free space you need to try
const std::filesystem::space_info spaceInfo = std::filesystem::space(dir);
cout << static_cast<std::intmax_t>(spaceInfo.free) << endl;
Here dir = "/path/to/dir/";
Refer cppreference
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I get this error:
Thread 1: EXC_BAD_ACCESS (code=1, address=0x68)
on the following line:
while(fscanf(f,"%d", &a[x])==1)
1st time trying to do my class homework in Xcode, used code blocks before and managed to run this same code on it, any help is much appreciated!
#include <cstdio>
int a[1001];
int main()
{
int aux1,aux2,aux3,x=0;
FILE *f,*g;
f=fopen("1.in","r");
g=fopen("2.out","w");
while(fscanf(f,"%d", &a[x])==1) //HERE
{
aux1=a[x];
aux2=0;
aux3=0;
while(a[x]!=0)
{
aux2=aux2*10+a[x]%10;
a[x]=a[x]/10;
aux3=aux3*10+9;
}
if(aux3-aux2==aux1)
fprintf(g,"1 ");
else fprintf(g,"0 ");
x++;
}
fclose(f);
fclose(g);
return 0;
}
To find out if you put the in and out files in the working directory you must try to print the read numbers in a terminal, if it doesn't print anything then I your .in and .out files are outside the working directory.
Debug:
After this line :
fscanf(f,"%d", &n);
do:
printf("%d", n);
if it prints the number well, guess your files are in the working directory, just make sure .out and .in are in the same directory and that's it.
Make sure that you actually opened 1.in file by checking what open() had returned. Make sure that you do not go outside of array bounds, if x reach 1001, something bad may happen, it's an Undefined Behaviour.
The problem was that I placed 1.in and 1.out outside the working directory, to fix this had to go to Product>Scheme>Edit Scheme>Run>Options and set a custom "Working Directory" where I placed the 1.in and 1.out files. Thanks for the help guys.
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I am reading a piece of code written by others, there is one line like this:
cout << "Data Loaded" << endl;
it seems nothing strange, however, the actually output is：
[18607330327, 18790481919] [19144201237, 19327352831] [20754813973, 20937965567] [21291684885, 21474836479] [21474836482, 21653864362] [22011707392, 22190735274] [23622320128, 23801348010] [24159191040, 24338218922] [27197264917, 27204255743] [27205653525, 27212644351] [27230819349, 27230959453] [27233615872, 27235153757] [30064771072, 30067638186] [30073159680, 30076026794] [30098325504, 30098440106] [30098456576, 30098536200] Data Loaded
where does the extra output come from? if I comment that line, then, nothing is output.
I then include the <cstdio> and replace that line by puts("Data Loaded"), still, the extra info get printed.
cout is a buffered output stream, and endl not only creates a new line, it also flushes the buffer. Without the flushing of the buffer it might happen that you do not see the output of a previous cout.
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Closed 9 years ago.
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I have hundreds of files in a folder like:
mp_12345.dat
mp_23455.dat
mp_12323.dat
mp_44445.dat
.
.
.
I want to rename all file to another folder:
Ind_somecircle_mp_12345.mbin
Ind_somecircle_mp_23455.mbin
Ind_somecircle_mp_12323.mbin
Ind_somecircle_mp_44445.mbin
.
.
And so on.
source folder: /home/dir1/foo/
destination folder: /home/dir2/foo/
I am looking for C or C++ code to do so.
Thanks in advance.
Actually this would be a better job for a shell script, but if you insist on C then rename(src, tgt); is what you are looking for.
If you want to read the filenames from the directory, you must use opendir and readdir to loop through the files.
A short sample:
void main(int c,char **args)
{
DIR *dir;
struct dirent *dent;
dir = opendir("mydir);
if(dir!=NULL)
{
while((dent=readdir(dir))!=NULL)
printf(dent->d_name); <-- rename
}
close(dir);
}
If you insist on using C/C++ for the job you need to use
opendir - http://linux.die.net/man/3/opendir, readdir - http://linux.die.net/man/3/readdir to get the list of files
That use rename - http://linux.die.net/man/2/rename to change the filename of a file