binaryfiles - how to open and read a binary file in C++ by a given bin file? -

is there me check did wrong? or explain why? beginner , tried best open binary file. runs out "file open" "0". nothing came out.

the objective: count3s program opens binary file containing 32-bit integers (ints). program count number of occurrences of value 3 in file of numbers. objective learn opening , accessing files , apply knowledge of control structures. name of file containing data used program "threesdata.bin".

my code below, please me if know it. thank in advance!

#include <iostream> #include <fstream> using namespace std;  int main() { int count=0 ; ifstream myfile; myfile.open( "threesdata.bin", ios::in | ios :: binary | ios::ate);  if (myfile) {     cout << "file open " << endl;     cout << count << endl;    }  else      cout << "cannot open it" << endl;   return 0;     } 

first of should read file opened in binary mode

  myfile.read (buffer,length); 

where buffer should defined as

  int data; 

and used as

  myfile.read (&data,sizeof(int)); 

the second important point reading file more 1 number - need loop controled condition check stream. example:

  while (myfile.good() && !myfile.eof())   {        // read data        // check , count value   } 

and last thing, should close file, oppened, after finished reading:

  myfile.open( "threesdata.bin", ios::binary);    if (myfile)   {        while (myfile.good() && !myfile.eof())        {            // read data            // check , count value        }        myfile.close();        // output results    } 

and additinal tips:

1) int not 32-bit type, consider using int32_t <cstdint>; , if data has more 1 byte, may byte order important, not mentioned in task description

2) read allows reading more 1 data object per 1 call, in case should read array instead of 1 variable

3) read , try examples references , other available resources this.