Splitting a function into 3 more functions.

[inukshuk]

I am trying to understand functions, or how to make one that calls another function, and i am trying to use as many functions as possible in this code.
I want to learn how i can split into 3 more functions and call from main the 3 functions. Any suggestions?

//Pointers to structures
#include <iostream>
#include <string>
#include <sstream>
#include <conio.h>

using namespace std;

//void func1 ();
//void func2 ();
//void func3 ();
struct movies_t {
       string title;
       int year;
};


int main () {
    string mystr;
    
    movies_t amovie;
    movies_t * pmovie;
    pmovie = &amovie;
 // split 1  
 //  func1 (); 
    cout << "Enter title: ";
    getline (cin, pmovie ->title);     
 // split 2  
 //  func2 ();                           
    cout << "Enter year: ";
    getline (cin,mystr);
    (stringstream) mystr >>pmovie ->year;
 // split 3 
 // func3 ();
    cout << "\nYou have entered:\n";
    cout << pmovie->title;
    cout <<" (" << pmovie->year << ")\n";
 //    
    getch();
    return 0;
}

//void func1 () {
//}
//void func2 () {
//}
//void func3 () {
//}
// 

[Chervil]

What's holding you back? Do you know how to use functions? If not, study the tutorial and then have a go: http://www.cplusplus.com/doc/tutorial/functions/

[inukshuk]

This is how i think it should be.

//Pointers to structures
#include <iostream>
#include <string>
#include <sstream>
#include <conio.h>

using namespace std;

void func1();
void func2();
void func3();

struct movies_t {
       string title;
       int year;
};


int main () {
    string mystr;
    
    movies_t amovie;
    movies_t * pmovie;
    pmovie = &amovie;
 //
   func1(); 
 //                                
    func2();
 //  
    func3();
 //    
    getch();
    return 0;
}
    
void func1(){
      cout << "Enter title: ";
      getline (cin, pmovie ->title);
      return 0;
}
void func2(){
     cout << "Enter year: ";
     getline (cin,mystr);
     (stringstream) mystr >>pmovie ->year;
     return 0;
}
void func3(){
      cout << "\nYou have entered:\n";
      cout << pmovie->title;
      cout <<" (" << pmovie->year << ")\n";
      return 0;
}

[Chervil]

I've not studied that in depth, Does it compile and run ok?

One thing, you can't return anything from a function declared as void, so return 0; is incorrect. Sometimes a plain return; might be useful, for example in an if statement.

[inukshuk]

It does not compile, in my functions i think i must pass something in the ()
func1 has a string, func2 has a int and func3 has both a string and an int. I think i have to edit that to reflect that data.

[Raezzor]

Ya, you'll have to pass the pointer to the functions then use the format pointer->member to access the structure members, either to input data to them or to read data out of them. Then to call the function you just use func1(pmovie)

[inukshuk]

How should it be?

//
void func1(pmovie);
//
int main () {
//
func1(*pmovie);
//
void func1(pmovie){
}

[inukshuk]

This is what i have so far but it is not compiling.

//Pointers to structures
#include <iostream>
#include <string>
#include <sstream>
#include <conio.h>

using namespace std;

void func1(pmovie);
void func2(pmovie);
void func3(pmovie);

struct movies_t {
       string title;
       int year;
};

int main () {
    string mystr;
    
    movies_t amovie;
    movies_t * pmovie;
    pmovie = &amovie;
//  
    func1(*pmovie); 
//                                
    func2(*pmovie);
//  
    func3(*pmovie);
//    
    getch();
    return 0;
}
    
void func1(pmovie){
      cout << "Enter title: ";
      getline (cin, pmovie ->title);
      return ;
}
void func2(pmovie){
     cout << "Enter year: ";
     getline (cin,mystr);
     (stringstream) mystr >> pmovie ->year;
     return ;
}
void func3(pmovie){
      cout << "\nYou have entered:\n";
      cout << pmovie->title;
      cout <<" (" << pmovie->year << ")\n";
      return ;
}

[Zhuge]

'pmovie' in the function parameter list needs to have a type. Just add 'movies_t*' in front of it.

[inukshuk]

I am still getting a lot of errors.

//Pointers to structures
#include <iostream>
#include <string>
#include <sstream>
#include <conio.h>

using namespace std;

void func1(movies_t * pmovie);
void func2(movies_t * pmovie);
void func3(movies_t * pmovie);

struct movies_t {
       string title;
       int year;
};

int main () {
    string mystr;
    
    movies_t amovie;
    movies_t * pmovie;
    pmovie = &amovie;
//  
    func1( pmovie); 
//                                
    func2( pmovie);
//  
    func3( pmovie);
//    
    getch();
    return 0;
}
    
void func1(movies_t * pmovie){
      cout << "Enter title: ";
      getline (cin, pmovie ->title);
      return ;
}
void func2(movies_t * pmovie){
     cout << "Enter year: ";
     getline (cin,mystr);
     (stringstream) mystr >> pmovie ->year;
     return ;
}
void func3(movies_t * pmovie){
      cout << "\nYou have entered:\n";
      cout << pmovie->title;
      cout <<" (" << pmovie->year << ")\n";
      return ;
}

[Zhuge]

And the errors are?

[inukshuk]

Edited the code a little.
Now the errors are

https://dl.dropbox.com/u/8616586/error.PNG

//Pointers to structures
#include <iostream>
#include <string>
#include <sstream>
#include <conio.h>

using namespace std;

struct movies_t {
       string title;
       int year;
};

void func1(movies_t * pmovie);
void func2(movies_t * pmovie);
void func3(movies_t * pmovie);

int main () {
    string mystr;
    
    movies_t amovie;
    movies_t * pmovie;
    pmovie = &amovie;
//  
    func1( pmovie); 
//                                
    func2( pmovie);
//  
    func3( pmovie);
//    
    getch();
    return 0;
}
    
void func1(movies_t * pmovie){
      cout << "Enter title: ";
      getline (cin, pmovie ->title);
      return ;
}
void func2(movies_t * pmovie){

     cout << "Enter year: ";
     getline (cin,mystr);
     (stringstream) mystr >> pmovie ->year;
     return ;
}
void func3(movies_t * pmovie){
      cout << "\nYou have entered:\n";
      cout << pmovie->title;
      cout <<" (" << pmovie->year << ")\n";
      return ;
}

[Zhuge]

func2() is using something called mystr, but that isn't defined inside func2()'s scope.

[inukshuk]

Yes but i do not know how to add that so it can be used by func2

[Zhuge]

You just need a random temporary string to store some input data, so why not just declare a local variable inside func2()?

[inukshuk]

I have a string mystr inside main, cant i use that?

[inukshuk]

This concludes this exercise, i have pasted the final code for further reference. The initial code was taken from the cplusplus tutorial, pdf, page 80.

//Pointers to structures
#include <iostream>
#include <string>
#include <sstream>
#include <conio.h>

using namespace std;

struct movies_t {
       string title;
       int year;
};

void func1(movies_t * pmovie);
void func2(movies_t * pmovie);
void func3(movies_t * pmovie);
                              //prototype must be under struct
int main () {
//  string mystr;       //*remove here
    
    movies_t amovie;
    movies_t * pmovie;
    pmovie = &amovie;
//  
//      cout << "Enter title: ";
//      getline (cin, pmovie ->title);
    func1( pmovie); 
// 
//      cout << "Enter year: ";
//      getline (cin,mystr);
//     (stringstream) mystr >>pmovie ->year;                               
    func2( pmovie);
//  
//    cout << "\nYou have entered:\n";
//    cout << pmovie->title;
//    cout <<" (" << pmovie->year << ")\n";
    func3( pmovie);

//    
    getch();
    return 0;
}
    
void func1(movies_t * pmovie){
      cout << "Enter title: ";
      getline (cin, pmovie ->title);
      return ;   //added return
}
void func2(movies_t * pmovie){
     string mystr;           //*added here
     cout << "Enter year: ";
     getline (cin,mystr);
     (stringstream) mystr >> pmovie ->year;
     return ;   //added return
}
void func3(movies_t * pmovie){
      cout << "\nYou have entered:\n";
      cout << pmovie->title;
      cout <<" (" << pmovie->year << ")\n";
      return ;   //added return
}

Thanks to those who helped.