Uber-N00B question

[SeijuroHiko]

First off I'd like to say hailz to you all! I'm your newest newbie trying to get a good grasp of programming C/C++/C#. Unfortunetly, I've got a loooong ways to go. With your help, I know I can make it.

My first question is rather tricky.... well... for me... :sad:

I'm using Mac OS X 10.2.6 on Project Builder, just doing Foundation C, but when I use scanf, it never seems to work quite right...

[IMG]http://uploader.unrealboards.com/uploads22/scanf probs.jpg[/IMG]

So my question is: why in the world is it asking for the scanf values before displaying my printf functions? How do I correct this?

[marceta]

get a PC!!!

[SeijuroHiko]

:rolleyes:

[Dani]

Please only offer helpful suggestions. I'm confused - when you run the program, the 2 and 5 are printed to the top of the screen automatically? Or did you enter them, or?

[Killer_Typo]

he is saying that he entered them and it asks for them when he starts instead of after the print out. let me try my hand with the code for a bit and ill see if i can help out. (not likely but ill try :))

[Killer_Typo]

/////////////////////////////////////////////////////
///program that takes one value a and places/////////
///it to the power of another value b, defining//////
///the power function by c///////////////////////////
/////////////////////////////////////////////////////
 
#include <stdio.h>
#include <math.h>
int main()
{
	  int a;   // defining the integer a which will be to the power of b
	  int b;   // defining the integer b which will be the integer being raised to some power
	  int c;   // defines the power function used to put a to the power of b
 
 
	  printf("Welcome\nThis Program takes  user-defined numbers\n(a and b respectivly), and puts 'a' to the power of 'b'\nPlease enter your value of 'a' below:\n");
	  scanf("%i", &a);
	  printf("\n\nGood, now enter your value for 'b':\n");
		 scanf("%i", &b);
	  printf("\n\nCOMPUTING");
		  c = pow(a,b);
	  printf("\n\nThe value of %i^%i is %i", a, b, c);
		 return 0;
}

ok so heres what i wrote and it works perfectly fine, you have to have some kind of pause or break between the scanf and c=pow or else it will give you 1^12345678..... and so and so forth. also you should comment your work more so its easier to read, its a good habbit to get into, and it will pay off in the long run.

try not setting your variables to anything IE dont set int a to anything if you know that your going to define it later in the code.

also, its good practice to space your code out so that it is readable.

IE x = "some value"
Not
x="somevalue"

its easier to read the first one over the second one.

[SeijuroHiko]

Well, I plugged in your code, Killer_Typo, and it's still doing the exact same thing... it won't come up with anything until the 2 variables are defined by the user. I tried using breakpoints, but my newbie butt doesn't even know what those are for, so of course it doesn't work... how do you implement a break or a pause?

Sorry the code is sloppy, I just cranked it out real quick having fun and testing what *little* I know. I wasn't planing on having to post it online to get it fixed...

Man this compiler is weird! Talk about non-linear thinking!

When my programs go beyond 25-30 lines, I'll start noting the code.

[Killer_Typo]

i didnt have any break points, the code up there is exactly what i compiled and ran, and it worked great. are you running this from the command prompt? or macs version of it at least? i use windows so im not sure what your problem with it is. maybe someone with a mac can help you better.

[FireNet]

Hey I think you guys are barking up the wrong tree.

scanf() works with options you sepecify.By options I mean all the stuff you specify in the " ".So it also means you can have multiple options too.

some options
-------------
%s       string (char *)
%d       int
%f       float

you can also use scanf() like this ie how to specify multiple options

scanf("%d,%f",int_val,float_val);

Helps???

[Dave Sinkula]

Ah, yes, scanf. Trouble is almost guaranteed until you decide to quit using it.

[SeijuroHiko]

Dave, I wish I knew that going into this... *sigh*

FireNet- This is what I came up with:

///////////////////////////////////////////////////////////////////////
/////////////////////  Simple Application here:  //////////////////////
///////  Allz we're doing is asking the user for 2 variables,  ////////
////////  a and b, put a to the power of b, and return that to ////////
///////////  c for display. Code should be self-explanitory.  /////////
///////////////////////////////////////////////////////////////////////


#import <Foundation/Foundation.h>

int main (int argc, const char * argv[]) 
{
    int a;
    int b;
    int c; 
    
    printf("CAN YOU FEEL THE POWER???\nJust enter 2 variables (a and b respectively)\nThis program will calculate a^b and return the result.\nEnter your to variables below:\n"); //He feels the pwer! ^_^
    
    scanf("%d, %d", &a, &b); //Hope this works...
    
    c = pow(a, b); // The one line of actual math...
    
    printf("%i^%i=%i", a, b, c);  //Display the values as a^b=c
    
    return 0;
}

It's still doing the same thing, only now, when I enter '5', it goes right through the math somehow getting '4' for 'b'. When I enter '7' for 'a', '4' for 'b' is still there...

Knowing me, I probably implemented the code wrong...

[Dave Sinkula]

One of the recommendations, if you followed the link I previously posted, was to use fgets and sscanf. For example,

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

int main(void) 
{
   double a, b, c; 
   char buffer [ BUFSIZ ];

   puts("CAN YOU FEEL THE POWER???\n"
		"Just enter 2 variables (a and b respectively)\n"
		"This program will calculate a^b and return the result.\n"
		"Enter your to variables below:");
   fflush(stdout);

   if ( fgets(buffer, sizeof buffer, stdin) )
   {
	  if ( sscanf(buffer, "%lf%lf", &a, &b) == 2 )
	  {
		 c = pow(a, b);
		 printf("%g ^ %g = %g\n", a, b, c);
	  }
   }

   return 0;
}

/* mu output
CAN YOU FEEL THE POWER???
Just enter 2 variables (a and b respectively)
This program will calculate a^b and return the result.
Enter your to variables below:
5 4
5 ^ 4 = 625
*/

[SeijuroHiko]

Apologies, Dave. I didn't realize that was a link.

I'll plug that in later tonight (IMPORT RACES!!! ^_^ ) and let ya know how it works... looks good from here!

Thanks for the help, Dave.

[SeijuroHiko]

OK! that's it... I give up... I'd never use scanf/sscanf anyways, so screw it.

Dave, you got pretty close with your idea.

[IMG]http://uploader.unrealboards.com/uploads22/scanf sucks.tiff[/IMG]

I tried about 3 or 4 variations of this code, but none got me really any closer...

Thanks for your help guys, but I'm giving up... I'm better off wasting my time on real-world code implementation...

[FireNet]

try doing this

int a,b,c,d;

scanf("%d%d%d",a,b,c);

d = a+b+c;

printf("The answer is:%d",d)

NEVER EVER GIVE UP

[SeijuroHiko]

Works just fine...

[IMG]http://uploader.unrealboards.com/uploads22/scanf blows nut.tiff[/IMG]

What my n00b logic is telling me is that main() wants to define the variables ASAP, overriding the printf() function...

Would defining the double variables in a header possibly overcome this?

:confused: