Thread: Wrong variable value assigned

Code:

#include <stdio.h>


int main()
{
 int n,a;
 int calc,sum,x,i,final_a;
 while(scanf("&#37;d %d",&n,&a) == 2)
     {
      sum=0;
      printf("n:%d -- ",&n);
      for(i=1; i<=n; i++)
                {
                 calc = 0;
                 for(x=1;x<i;x++)
                    {
                     final_a = a;
                     final_a = final_a * a;
                     
                    }
                 calc = i * final_a;
                 sum = sum + calc;
                }
      printf("%d\n",sum);
     }
}

No variable prints out correctly :S

Remember: printf takes a value, scanf takes an address. So while you do

Code:

scanf("%d", &n);

you do

Code:

printf("%d", n);

Aha. What a stupid mistake sorry about that.
Hey now I finally got the program working 100%.

Code:

#include <stdio.h>

int main()
{
 int n,a;
 int calc,sum,x,i,final_a;
 while(scanf("%d %d",&n,&a) == 2)
     {     
      sum = 0;
      for(i=1; i<=n; i++)
                {
                 final_a = a; 
                 if(i == 1)
                      {
                           
                      }
                 else
                 {  
                 for(x=1;x<i;x++)
                    {
                     final_a = final_a * a;                    
                    }
                 }
                 calc = i * final_a;
                 sum = sum + calc;
                }
      printf("%d\n",sum);
     }
}

But when I submit it to online judge acm; it always says runtime error. The code compiles and runs (with input file and output as well) on a unix box no problems whatsoever. So anybody got any ideas?

Nevermind. I found my own error!
I had to add "int argc, char* argv[]" and "return 0;" to my code for it to compile with no warnings.
Thanks guys for all the help!!!

yuh well now im just confused...
here is my final code that i submitted to the judge and got a "wrong answer" reply to...

Code:

/* CSC1140@ 07611201 74kzYkXl 10523 */
#include <stdio.h>

int main(int argc, char* argv[])
{
 int n,a;
 int calc,sum,x,i,final_a,count=0;
 while(scanf("&#37;d %d",&n,&a) == 2)
     {     
      count++;
      sum = 0;
      for(i=1; i<=n; i++)
                {
                 final_a = a; 
                 if(i == 1)
                      {
                           
                      }
                 else
                 {  
                 for(x=1;x<i;x++)
                    {
                     final_a = final_a * a;                    
                    }
                 }
                 calc = i * final_a;
                 sum = sum + calc;
                }
      if(count == 1)
      {
          printf("%d",sum);
      }
      else
      {
          printf("\n%d",sum);
      }
     }
     return 0;
}

i know its probably over-complicated; but it was all i could think of to make sure there were no extra "\n" at the end of output.
I tested it for many different inputs and the output is correct each and every time...

I might be mistaken, but I think you're supposed to have a new-line character at the end of the input. (IOW, I wouldn't bother with the if, but just print "%d\n" each time.) The other stuff looks over-complicated, but correct. (E.g., the if (i==1) test is unnecessary, since if i was 1, the for-loop would never actually happen.)

At first I left the code without the if statement at the very end (the one that gets rid of the last \ n) but I got wrong answer as well. Im pretty sure my calculations are all correct. But you don't see anything wrong with the code do you?

Thanks

The only other thing I can think of offhand is overflow; don't know if you know limits on how large your numbers are supposed to get.

N and A (integer, 1<=N<=150 & integer, 0<=A<=15)
Does that help?

Aha.
Yes numbers for n and a that are getting to the highest do cause negative answers (which i assume means overflow)...
I included the extra header; it helped edge the overflow to a larger number. I then tried unsigned; but same results.

Thanks for all the help guys.. But I think I am finally going to give up on this problem...
I mean I solved the overflow problem and made sure the program worked for those range of numbers... everything works now and displays exactly as it should... I tried it with and without the endline at the end... but all I get are "Wrong Answers".
Again thank you for all of your help and I have learned ALOT from this post!
But if you do think of why my code would produce a wrong answer; please let me know. Id love to learn why so i dont make that mistake again...
thanks