Member Avatar for CreativeCoding

So i'm working on this program. And long story short, I need something that will allow the user to choose the dir/file and have the system set read-only to true.

Here is a piece that I worked on. Only it crashes on the system line.

try
  {
    clear;
    char* dir;
    cout << "Enter folder location > ";
    cin >> dir;
    char l_szCommand[50];
    sprintf(l_szCommand, "attrib +r %s", dir);
    system(l_szCommand);
    Sleep(5000);
  }
  catch (int e)
  {
    clear;
    cout << "Error: " << e << endl;
    system("PAUSE");
  }

Forgive me for anything wrong with this for I am just about a few hours new to C++. And i'm only 13...

  • 3 Contributors
  • 5 Replies
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  • 2 Days Discussion Span
  • Latest Post Latest Post by thomas_naveen

Dani AI

Generated

Brief expert note: the original crash and the strange "File not found - Ä" come from reading into an uninitialised or wrong-sized C buffer and from not handling spaces in paths. As pointed out, allocate (or better: use a safe string type) before storing input; and as suggested, use the full path. The fastest, safest fix is to stop using raw char* and sprintf for command construction.

A minimal, safe example that keeps the attrib approach (Windows) — reads the whole line, quotes the path (so spaces are handled), and shows the command for debugging:

#include <iostream>
#include <string>
#include <cstdlib>

int main() {
    std::string path;
    std::cout << "Enter folder location > ";
    std::getline(std::cin, path);
    if (path.empty()) return 1;
    std::string cmd = "attrib +r \"" + path + "\"";
    std::cout << "Running: " << cmd << '\n';
    int rc = std::system(cmd.c_str());
    std::cout << "system returned " << rc << '\n';
    return 0;
}

Better approach (recommended for production) is to call the platform API directly instead of invoking a shell. On Windows, use GetFileAttributesW / SetFileAttributesW to add FILE_ATTRIBUTE_READONLY (and use wide strings for Unicode paths):

#include <windows.h>
#include <string>

bool setReadOnly(const std::wstring &p) {
    DWORD a = GetFileAttributesW(p.c_str());
    if (a == INVALID_FILE_ATTRIBUTES) return false;
    a |= FILE_ATTRIBUTE_READONLY;
    return SetFileAttributesW(p.c_str(), a) != 0;
}

Notes and troubleshooting: wrap paths in quotes when using system(); check return codes; print the command for debugging; prefer std::getline to capture spaces; avoid manual new[]/delete[] to prevent leaks and UB; remember the read-only attribute on a folder is treated specially by Explorer and does not enforce NTFS ACLs — to prevent write access change file/ACL permissions or use std::filesystem::permissions (C++17) / proper ACL APIs for robust permission control.

Recommended Answers

All 5 Replies

Member Avatar for thomas_naveen

Try allocating memory to your dir variable. Similar to the command variable.

Member Avatar for CreativeCoding

Hmm. That seemed to fix it. But now I have a new problem. Whenever I enter a location, it gives me

File not found - Ä

Also, I don't much about memory allocation but after a few tutorials, i wrote this update

try
  {
    clear;
    char * dir;
    cout << "Enter folder location > ";
    cin >> dir;
    dir = new char [50];
    char l_szCommand[50];
    if (dir == 0) {
  clear;
  cout << "Error: memory could not be allocated" << endl;
  pause;
  }; 
    sprintf(l_szCommand, "attrib +r %s", dir);
    system(l_szCommand);
    Sleep(5000);
  }
  catch (int e)
  {
    clear;
    cout << "Error: " << e << endl;
    pause;
  }
Member Avatar for thomas_naveen

Memory should be allocated before you use the pointer for storing data.

In the current code you are taking in data to a pointer which could be pointing anywhere and then pointing that pointer to a fresh memory location.

You lose the input data in this way.

Make the 7th line your 5th line and check out the results.

Edited by thomas_naveen because: n/a
Member Avatar for abhimanipal

If after resolving the memory issue you are still getting file not found, I will suggest that you take the full path name of the directory

Member Avatar for thomas_naveen

Kindly let us know whether your issue is resolved?

If so, mark the thread as solved.

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