Thread: Trouble with a simple array

thanks, ive figured it out....it seems when i switched computers, it would work...don't know why mine wasn't working.

Originally Posted by ssharish2005

there u go the working code.

Code:

#include <stdio.h>
#include <math.h>
#define SIZE 100

int temp[SIZE];

int main (void)
{
	int i, sum, sum_sqr,tempi;
	double mean, st_dev;
	FILE *inp;
	
	inp = fopen("C:\\Program Files\\Miracle C\\temperature.txt", "r");
	
	if (inp == NULL)
	{
		printf("ERROR OPENING THAT FILE\n");
	}

	/* Gather and prints all the data from the file */
	for (i = 0; i<SIZE; i++) 
	{
		if(fscanf(inp, "%d", &temp[i])!=1)
		break;
		printf("%d\n", temp[i]);
	}

	/*Computes the sum and the sum of the squares of all the data*/
	sum = 0;
	sum_sqr = 0;
	tempi=i;
	for (i = 0; i < tempi; i++)
	{
		sum+=temp[i];
		sum_sqr += temp[i] * temp[i];
	}
	/*Computes and prints the mean and standard deviation*/
	mean = (double)sum / SIZE;
	st_dev = sqrt(sum_sqr / SIZE - mean * mean);
	printf("The mean is %.2f\n", mean);
	printf("The standard deviation is %.2f.\n", st_dev);
	
	fclose(inp);
    getchar();
	return (0);
}
/*myoutput
1
2
3
4
5
6
7
8
9
The mean is 0.45
The standard deviation is 1.34.
*/

ssharish2005

You've got a logic error here, dividing by SIZE will only work when you actually read 100 items.....you're reading far less, which means youre computations are wrong, you need to divide by the number of items you actually read in, so you'll have to keep track of that somehow.