Hi guys,

 

I'm writing a simple program which takes similar values from a user at the keyboard. But I've run into some issues and I'm not sure why. It MUST be to do with the conversion specifiers but I just can't figure it out :/

 

Here's the code:

 

/* 
* File:   main.c
* Author: daniel
*
* Created on March 27, 2012, 6:49 PM
*/

#include <stdio.h>
#include <stdlib.h> 
#include "main.h"

#define MAX_LAT 52.75
#define MIN_LAT 51.5
#define MAX_LNG 6.5
#define MIN_LNG 4.75

#define REQ_LAT 0.1
#define REQ_LNG 0.2

/*
* This function takes a location value from the user and if any ships are 
* within 0.1 latitude or 0.2 longitude of this position the function will produce
* a message and log the information appropriately
*/
int main(int argc, char** argv) 
{
ship s; // struct in the headerfile containing latitude and longitude of type double
double user_lat;
double user_lng;

// THESE TOP TWO PRINTFS WILL BE REPLACED BY VALUES TAKEN FROM OUR
// DATA ENTRY PROGRAM

printf("Please enter a specific latitude value for the vessel: ");
scanf("%lf", s.latitude);

printf("%lf", s.latitude); //used for de-bugging

printf("Please enter a specific longitude value for the vessel: ");
scanf("%lf", s.longitude);

printf("Now enter a latitude area you'd like to check in: ");
scanf("%le", &user_lat);

printf("Now enter a corresponding longitude area you'd like to check in: ");
scanf("%le", &user_lng);

//IF LATITUDE/LONGITUDE VALUES OF THE SHIP ARE WITHIN 
//USER'S GIVEN VALUES IN ACCORDANCE WITH THE REQUIRED LAT AND LNG
//PRODUCE A MESSAGE

// THIS LOOP WILL DEAL WITH WHETHER A SHIP IS WITHIN THE BOUNDARIES OF
// A USER'S CHOSEN LAT AND LNG VALUES AND ALSO DEAL WITH WHETHER OR NOT SHIP'S
// ARE EVEN IN St.George's CHANNEL AT ALL! 

return (EXIT_SUCCESS);
}

 

Now the program runs and lets me enter the latitude and longitude figures but then produces the RUN FAILED error message.

 

For reference here's the output:

Please enter a specific latitude value for the vessel: 51.425

0.000000Please enter a specific longitude value for the vessel: 51.233

 

RUN FAILED (exit value 1, total time: 10s)

 

Anyone got any ideas? To me it should just at the moment take four values from the user :/

 

Thanks guys,

TP12

is the structure members latitude and longtitude of type pointer? You need to feed scanf() with a variable of type pointer, e.i. using the address-of operator. Probably just a typo on your part though.

Here is a compiled code that works fine: C++, C

 

.. I think this is the problem:

 

scanf("%lf", s.latitude);

 

a. if s.latitude is a pointer, it must be allocated before used

 

b. if s.latitude is a variable, it must be preceded by &

 

.. if your code still doesn't work then check these:

 

1. within the file: main.h

 

2. why name it main.h (which is assumed to be accompanied with main.c\main.cpp as its definition), change that file name

 

3. The compiler you're using, try another