C: testing multiple consecutive array values concurrently.?

acvoight · 11-22-2010, 07:26 PM

I'm having a bit of trouble figuring out if consecutive values in an array are the same; I don't know how to approach the problem.

Basically, I am provided with a file "temp.dat" with 30 high temperatures (integers) in it. The program is supposed to read them in and compute/print the average. Then it is supposed to print the temperature of each day and, in addition, display a + by each day that is over the average, but only if it is above the average high for three or more consecutive days. This is the part I am stuck on. I'd appreciate any tips that would point me in the right direction

Full disclosure: This is a school project. Code:

Code:

#include <stdio.h>
#include <stdlib.h>
#define SIZE 31

int main() {

  FILE *data;
  int counter, days, i, month_l, sum_t, temperature;
  float average_t = 0;
  int array_t[SIZE];
  char array_c[SIZE];

  i = counter = days = sum_t = 0;

  printHeading();

  printf("Enter the number of days data was collected for:\t");
  scanf("%d",&month_l);

  if ((data = fopen("temp.dat","r")) == 0){
    printf("No such file found. Please place temp.dat in the program's directory.\n");
    exit(1);
  }  

  while(fscanf(data, "%d\n", &temperature) != EOF){
    array_t[i] = temperature;
    sum_t += temperature;
    i++;
  }

  average_t = sum_t / month_l;
  printf("The average temperature is %.2f\n", average_t);

  for(i = 0; i < month_l; i++){
    if(array_t[i] > average_t)
      array_c[i] = '+';
    else
      array_c[i] = ' ';
  }

  for(i = 2; i < month_l; i++){
    if((array_c[i-2] == '+') && (array[i-1] == '+') && (array[i] == '+')){
      //Not really sure what to do here to preserve values for >3 day consecutive above average high temperatures.
    }
      
  }

  for(i = 0; i < month_l; i++){
    printf("%d\t%d  %c\n", ++days, array_t[i], array_c[i]);
  }

}

Here's the data file if you need it:

Code:

acvoight · 11-22-2010, 07:56 PM

Well I was struck by some inspiration and came up with:

Code:

#include <stdio.h>
#include <stdlib.h>
#define SIZE 31

int main() {

  FILE *data;
  int counter, days, i, month_l, sum_t, temperature;
  float average_t = 0;
  int array_t[SIZE];
  char array_c[SIZE];

  i = counter = days = sum_t = 0;

  printf("Enter the number of days data was collected for:\t");
  scanf("%d",&month_l);

  if ((data = fopen("temp.dat","r")) == 0){
    printf("No such file found. Please place temp.dat in the program's directory.\n");
    exit(1);
  }  

  while(fscanf(data, "%d\n", &temperature) != EOF){
    array_t[i] = temperature;
    sum_t += temperature;
    i++;
  }

  average_t = sum_t / month_l;
  printf("The average temperature is %.2f\n", average_t);

  for(i = 0; i < month_l; i++){
    if(array_t[i] > average_t)
      array_c[i] = '+';
    else
      array_c[i] = ' ';
  }

  for(i = 2; i < month_l; i++){
    if(array_c[i] == '+'){
      if((array_c[i-1] == ' ') && (array_c[i+1] == ' ')){
        array_c[i] = ' ';
      }
      else if((array_c[i-1] == ' ') && (array_c[i+1] == '+')){
        if(array_c[i+2] == '+')
          array_c[i] = '+';
        else
          array_c[i] = ' ';
      }
      else if((array_c[i-1] == '+') && (array_c[i+1] == ' ')){
        if(array_c[i-2] == '+')
          array_c[i] = '+';
        else
          array_c[i] = ' ';
      }
    }
    else
      array_c[i] = ' ';
  }

  for(i = 0; i < month_l; i++){
    printf("%d\t%d  %c\n", ++days, array_t[i], array_c[i]);
  }

}

However, I would still very much appreciate tips on how "you" would solve this as this seems to be the worst way to solve it.

mac.tieu · 11-22-2010, 09:23 PM

Quote:

Originally Posted by acvoight

However, I would still very much appreciate tips on how "you" would solve this as this seems to be the worst way to solve it.

Code:

  average_t = sum_t / month_l;
  printf("The average temperature is %.2f\n", average_t);

  if (month_l > 0) // lowest item
    array_c[0] = (array_t[0]>average_t)?'+':' ';
  for(i = 1; i < month_l - 1; i++){
    if(array_t[i-1] > average_t) {
      array_c[i-1] = '+';
      if(array_t[i] > average_t && array_t[i+1] > average_t) {
        // Don't need to check these items again
        array_c[i] = '+'; array_c[i+1] = '+'; i+=2;
      }
    } else {
      array_c[i-1] = ' ';
      if (array_t[i+1] < average_t) {
        array_c[i] = ' '; i++;
      }
    }
  }
  // remain items
  if (month_l > 1)
    array_c[month_l-1] = (array_t[month_l-1]>average_t)?'+':' ';
  if (month_l > 2)
    array_c[month_l-2] = (array_t[month_l-2]>average_t)?'+':' ';

  for(i = 0; i < month_l; i++){
    printf("%d\t%d  %c\n", ++days, array_t[i], array_c[i]);
  }

Cheers,
MT.