Thread: Unused variables? (short code)

Code:

 #include <stdio.h>
  4 #define mile 5280
  5 #define kilometer 3282
  6 void instructions (void);
  7 int main()
  8 {
  9         int minutes;
 10         scanf("%d", &minutes);
 11         double seconds;
 12         scanf("%lf", &seconds);
 13         double totsec=(60*minutes)+(seconds);
 14         double fps =(mile)/(totsec);
 15         double mps=(1000.0/kilometer)*(5280.0/totsec);
 16         printf(" That is %.1lf feet per second, and %.2f meters per second.\    n",fps,mps);
 17
 18         return 0;
 19 }
 20
 21         void instructions()
 22         {
 23                 printf("This program will ask for the minutes and seconds fo    r the time it\ntook for a runner to run a mile.  The program will then calcu    late\nthe feet per second and meters per second for that runner.\n");
 24
 25
 26
 27         printf("\nMinutes for the runner: ");
 28         printf("Seconds for the runner: ");
 29
 30 }

It compiled fine. But when i run a.out, the program doesn't display any text nor prompt the user for input.
But as grumpy correctly pointed out. I cannot nest a function within main.

My goal is to ("Write and call a function that displays instructions to the program user".)

C does not support nesting functions inside functions.

There are probably error messages you haven't seen fit to mention, but the compiler will be emitting them because you have nested instructions() inside the body of main().

The compiler will probably be horribly confused after that, when compiling subsequent code. The errors and warnings given may or may not be valid.

Depending on age of your C compiler, variables must be defined at the top of blocks (before any executable statements).

Originally Posted by tmac619619

So what you're is i should put my calcuations, declared variables under main.

What you've said here is as clear as mud.

Originally Posted by tmac619619

And then put the void instructions function outside of main?

That is a corollary of the fact that function cannot be implemented inside functions.

Well where in your main do you call instructions?

As in

Code:

int main ( ) {
    instructions();
    // rest of code
}

Also, to prevent long lines, do this

Code:

printf("This program will ask for the minutes and seconds for the time it\n"
       "took for a runner to run a mile.  The program will then calculate\n"
       "the feet per second and meters per second for that runner.\n");

The compiler will automatically join the strings.

Just another hint to the OP - if you change your code, it is better to create a second post with the new code, and not edit your original code.


The original code you posted had the definition (implementation) of instructions() within the body of main(). However, you have since edited the first post and corrected that, so my subsequent replies appear without the context in which I wrote them.


Even though the definitions of functions cannot be nested, it is still necessary to write code to call your functions, as in Salem's post.