Thread: Jumping between functions

Newbie here! I was wondering if it is possible to jump back to a previous function in a program and if it is how would one go about doing it?

What i want is to be able to jump back to the main menu in main from the registration function. I thought return would allow me to do it, but i was wrong.

Code:

#include <stdio.h>
#include <math.h>
#include <stdlib.h>

#define BUF_SIZE 128

int Registration(int* user);
int Login(int* user); 
 
int main (int a)

{
	
	int user;	
	int log;
	int reg;
	char ans;
		
		printf ("Please select from the following...");
	
		printf ("\n1)[R]egister");
	
		printf ("\n2)[L]ogin");
	
		printf ("\n3)[U]nregister");
	
		printf ("\n");
	
		scanf  ("%c", &ans);
	
	{	 	 
			if (ans == 'l' || ans == 'L' || ans == '1')
				Login(&user);
			
			else if (ans == 'r' || ans == 'R' || ans == '2')
				Registration(&user);
	
			else 
				printf("Invalid!\n");
	}
}
		


int Registration(int* user)

{

	FILE *db;

	db = fopen("text.txt","a+");

		printf("Please enter registration user name here: ");

		fscanf (stdin, "%s", &user);

		fprintf(db,"%s \n",&user );

		fclose(db);

		printf("Registration Accepted!");

		getchar();
		
		return 0;

		
	
}

int Login(int* user)
{
	
	printf ("Enter Login name:");
	scanf  ("%d", &user);

}

How about something like:

Code:

int quit = 0;
while(quit == 0)
{
    DisplayMenu();
    DoOtherStuff();
    if( ans == 'q') quit = 1
}

Originally Posted by Nexus-ZERO

What i want is to be able to jump back to the main menu in main from the registration function. I thought return would allow me to do it, but i was wrong.

Of course return takes you back to main. But that's the key--it takes you back, that is, to where you called the function from in the first place. There's just nothing left to do there, anymore, since you set main up to only display the menu once and then stop. If you want to see the menu again, then your main program must continue to run in some sort of loop.

Code:

int main (int a)

There are a couple of ways to specify main, but this isn't one of them. You can do

Code:

int main(void)

or

Code:

int main(int argc, char *argv[])

Since you nowhere use a, I would suggest the first.

Your login function claims to return an int, but does not do so, causing your compiler to have to magically come up with one, somehow. You should either save the compiler the bother by returning something, or if you don't want to return anything, specify a return type of void.

Code:

int main( int argc, char *argv[] )
{
      int user;	  
      int log;
      int reg;
      char ans=0;
	
      while( ans != 'Q' || ans != 'q' )
      {
          printf ("Please select from the following...");
          printf ("\n1)[R]egister");
          printf ("\n2)[L]ogin");
          printf ("\n3)[u]nregister");
          printf ("\n4)[Q]uit");
          printf ("\n");
          scanf  ("%c", &ans);
    
          if (ans == 'l' || ans == 'L' || ans == '1')
	         Login(&user);
          else if (ans == 'r' || ans == 'R' || ans == '2')
	         Registration(&user);
          else if( ans != 'Q' || ans != 'q' )
                         return 0;
          else
	         printf("Invalid!\n");
      }
      return 0;
}

Well the way you where calling the Login function looks not right to me. What are you trying to do. And your need to indented properly. Check with Preview button before you post. The above code will explain the way you want to get back to the main function using return.

ssharish

No <setjmp.h> stuff is needed. Just a common menu being returned to from a function.

As noted, the menu display just needs to be:

in a loop that repeats until you want to stop or quit.

Return is the standard way to go back to the calling menu, from your function.