Passing array right

I'm trying to pass an array...and add up it's total, however i'm always getting 0 as my answer. Someone tell me what i'm doing wrong...thanks...eventually it's going to calculate standard deviation...but i need that dang array to be passed

Code:

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

int st_dev(float a[]);

int main()
{
        float numbers[20];
        int count;

        printf("Enter 20 Numbers: ");

        for (count = 0; count < 20; count++)
        {
                scanf( "%d", (numbers + count));
        }

        st_dev(numbers);

}

int st_dev(float a[])
{
        float total;

        for (int i = 0; i < 20; i++ )
        {
                total = total + a[i];
        }
       
        printf("%4.2f\n", total);

        return total;

}

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You're passing the array just fine. The problem is that you're passing scanf() the %d modifier instead of %f. If it was an int array then %d would be the right choice, but since it's a float array you should be using %f.

Also:

Code:

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for (int i = 0; i < 20; i++ )

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That is not allowed in C. Declare your variables at the top of the function instead of inside the for loop statement like that.

And don't forget to inititalize total when you declare it. If you don't specifically set it to something then it will start off with some random garbage value.

You might want to consider rewriting total = total + a[i]; as total += a[i];. The way you have it will work fine, but I find the += method easier and clearer.

And initialize total.

Code:

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float total = 0;

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itsme mentioned that.

Quote:

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And don't forget to inititalize total when you declare it. If you don't specifically set it to something then it will start off with some random garbage value.

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But the post was edited, so it probably wasn't there when you posted.

Since total is a float, you can't really return it as an int. Actually, you don't have to return a value at all, because the function prints the value and you discard it anyway.

Wicked thanks alot for the help guys...it's always the small stuff that i miss

Appreciate it

Quote:

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Originally Posted by itsme86

Code:

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for (int i = 0; i < 20; i++ )

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That is not allowed in C.

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It's allowed in C99.

Quote:

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Originally Posted by cwr

It's allowed in C99.

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Code:

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itsme@itsme:~/C$ cat c99test.c
#include <stdio.h>

int main(void)
{
  for(int i = 0;i < 10;++i)
    printf("%d\n", i);

  return 0;
}
itsme@itsme:~/C$ gcc -Wall c99test.c -o c99test
c99test.c: In function `main':
c99test.c:5: error: 'for' loop initial declaration used outside C99 mode
itsme@itsme:~/C$ gcc -Wall --std=c99 c99test.c -o c99test
itsme@itsme:~/C$

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So it is...my bad.

No, C99 bad. ;)

Personally I hate that addition to the language. But I suppose I'm just being old.


Quzah.