Possible memory leak in string memory allocation - c++

Question

This is my code:
#include <string>
#include <iostream>
#include <cstdio>
#include <cstdlib>
std::string & fileread(const char * name)
{
FILE *fp = fopen(name,"rb");
size_t sz;
int i;
char *buff;
fseek(fp, 0, SEEK_END);
sz = ftell(fp);
fseek(fp, 0, SEEK_SET);
buff = (char *)malloc(sizeof(char)*(sz+1));
buff[sz] = '\0';
fread(buff,sz,1,fp);
std::string * rtstr = new std::string(buff);
free(buff);
fclose(fp);
return * rtstr;
}
int main(int argc,char * argv[])
{
std::string file_info(fileread(argv[1]));
std::cout<<file_info << std::endl;
return 0;
}
It is simply read one file, and print its content to screen.
In the function fileread, I use new std::string(buff); to get a std::string *, and return the point back. Will it cause memory leak? And if the answer is 'yes' , how to avoid it?
About use C in C++: fread is much faster than ifstream (tested with 1 billion random number)
My problem is about memory leak.

Answer 1

Return std::string by value. Don't worry, C++ will take care of not copying the object redundantly (unless you have a very old compiler).
Here is the code, fixed:
#include <string>
#include <iostream>
#include <cstdio>
#include <cstdlib>
std::string fileread(const char * name)
{
FILE *fp = fopen(name,"rb");
size_t sz;
int i;
char *buff;
fseek(fp, 0, SEEK_END);
sz = ftell(fp);
fseek(fp, 0, SEEK_SET);
buff = (char *)malloc(sizeof(char)*(sz+1));
buff[sz] = '\0';
fread(buff,sz,1,fp);
std::string rtstr(buff);
free(buff);
fclose(fp);
return * rtstr;
}
int main(int argc,char * argv[])
{
std::string file_info(fileread(argv[1]));
std::cout<<file_info << std::endl;
return 0;
}
I made only the small change necessary and ignored any other problems you might have in your code. Take care.

Answer 2

As Nawaz rightly commented: "DONT code C in C++. Use std::ifstream and std::string (not std::string*)". Here is the code in C++ to avoid all the issues:
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main () {
string line;
ifstream myfile ("myfile.txt");
if (myfile.is_open())
{
while ( getline (myfile,line) )
{
cout << line << '\n';
}
myfile.close();
}
else cout << "Unable to open file";
return 0;
}