Find all substring’s occurrences and locations

by 
string str,sub; // str is string to search, sub is the substring to search for

vector<size_t> positions; // holds all the positions that sub occurs within str

size_t pos = str.find(sub, 0);
while(pos != string::npos)
{
    positions.push_back(pos);
    pos = str.find(sub,pos+1);
}

Edit
I misread your post, you said substring, and I assumed you meant you were searching a string. This will still work if you read the file into a string.

More Related Contents:

  1. ‘printf’ vs. ‘cout’ in C++
  2. Which C I/O library should be used in C++ code? [closed]
  3. Why is iostream::eof inside a loop condition (i.e. `while (!stream.eof())`) considered wrong?
  4. Why does std::getline() skip input after a formatted extraction?
  5. Why would we call cin.clear() and cin.ignore() after reading input?
  6. How to print (using cout) a number in binary form?
  7. C++ Standard Library: How to write wrappers for cout, cerr, cin and endl?
  8. Does the C++ standard mandate poor performance for iostreams, or am I just dealing with a poor implementation?
  9. Restore the state of std::cout after manipulating it
  10. How to get IOStream to perform better?
  11. Difference between iostream and iostream.h
  12. How do I deal with the max macro in windows.h colliding with max in std?
  13. Standard no-op output stream
  14. stdio.h not standard in C++?
  15. How to print __int128 in g++?
  16. How do the stream manipulators work?
  17. Obtain a std::ostream either from std::cout or std::ofstream(file)
  18. How to disable buffering on a stream?
  19. Win32 – read from stdin with timeout
  20. How to make cout behave as in binary mode?
  21. Why can’t std::ostream be moved?
  22. Loading a file into a vector
  23. generic way to print out variable name in c++
  24. How to detect negative numbers as parsing errors when reading unsigned integers?
  25. How can I print 0x0a instead of 0xa using cout?
  26. Cannot open include file: ‘stdio.h’ – Visual Studio Community 2017 – C++ Error
  27. Reading files larger than 4GB using c++ stl
  28. Wrapping FILE* with custom std::ostream
  29. Output Unicode strings in Windows console
  30. Why are iostreams not copyable?

Leave a Comment