C++ function unable to another function and ends automaticly - c++

Question

So I was making a file editor using c++ and it has 3 functions and it needs to call each other to work properly.But When code tries to call other functions it end abnormly .
I tried changing the order of functions but it does nothing.It will compile properly without warnings
it needs output the contents of the file.
#include <iostream>
#include <fstream>
#include <bits/stdc++.h>
#include <string>
#include <iomanip>
#include <unistd.h>
#include <sstream>
using namespace std;/* std */
/* data */
char buffer;
std::string fname;
int reader(){
std::ifstream readfile;
readfile.open(fname.c_str());
readfile>>buffer;
std::cout << buffer<< '\n';
int write();
}
int options(){
cout << "************************"<< '\n';
cout << "* Starting File editor *"<< '\n';
cout << "************************"<< '\n';
cout << "* Enter Filename *"<< '\n';
cin >>fname;
cout << "Opening File"<<fname<< '\n';
int reader();
std::cout << buffer<< '\n';
}
int write(){
cout << "writing to file " << '\n';
std::ofstream writefile;
writefile.open(fname.c_str());
writefile<<buffer;
cout << "writing done " << '\n';
}
int main()
{
/* code */
options();
return 0;
}

Answer 1

options() is not calling reader(), and reader() is not calling write(). In both cases, you are simply declaring functions, not actually calling them.
int reader(){
...
int write(); // <-- a declaration, not a call!
}
int options(){
...
int reader(); // <-- a declaration, not a call!
...
}
int main() {
...
options(); // <-- a call, not a declaration!
..
}
Try this instead:
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
/* data */
char buffer;
std::string fname;
int reader(){
cout << "opening file " << fname << '\n';
std::ifstream readfile(fname.c_str());
readfile >> buffer;
std::cout << buffer << '\n';
}
int write(){
cout << "writing to file " << '\n';
std::ofstream writefile(fname.c_str());
writefile << buffer;
cout << "writing done" << '\n';
}
int options(){
cout << "************************"<< '\n';
cout << "* Starting File editor *"<< '\n';
cout << "************************"<< '\n';
cout << "* Enter Filename *"<< '\n';
cin >> fname;
reader();
write();
}
int main() {
/* code */
options();
return 0;
}

Answer 2

In addition to the comments above about calling the functions, it seems like it would be good to initialize buffer as a char array as shown below:
#include <iostream>
#include <fstream>
//#include <bits/stdc++.h>
#include <string>
#include <iomanip>
#include <unistd.h>
#include <sstream>
using namespace std;/* std */
/* data */
char buffer[]{"Short test"};
std::string fname;
void write(){
cout << "writing to file " << '\n';
std::ofstream writefile;
writefile.open(fname.c_str());
writefile<<buffer;
cout << "writing done " << '\n';
}
void reader(){
std::ifstream readfile;
readfile.open(fname.c_str());
readfile>>buffer;
std::cout << buffer<< '\n';
write();
}
void options(){
cout << "************************"<< '\n';
cout << "* Starting File editor *"<< '\n';
cout << "************************"<< '\n';
cout << "* Enter Filename *"<< '\n';
cin >>fname;
cout << "Opening File"<<fname<< '\n';
reader();
std::cout << buffer<< '\n';
}
int main()
{
/* code */
options();
return 0;
}

Answer 3

You can declare functions(not compulsory in your case) after all #include statements like:
int reader();
int write();
int options();
You call write function as write(); reader function as reader();
Since functions are not returning anything you could change int reader() to void reader(), int write() to void write() and so on. Keep main as int main() though.