Thread: Trying to figure what I'm doing wrong in this program

  1. #1
    Registered User
    Join Date
    Feb 2011
    Posts
    21

    Trying to figure what I'm doing wrong in this program

    I trying to do a program that allows you to enter 5 numbers in an array. Then it takes the values of the array calculates the sum, average, and median of the values. Then shows the values you enter into the code and display the results.

    In the getData function my for loop seem correct with enter the value this is place into the index memory slots from 0 to 4. Then it returns the values received it the array. The calculateValues function then takes the value then adds the sums of all the index values. Then that value is divided by the number of index slots in the array. Haven't figure out the median yet but when I print the results of the sum and average my values are not correct.

    For example my result will look like this:
    Code:
    Enter the array elements
    25
    36
    21
    23
    25
     Index  Item
      0  32        à    ■     0.00
      1  32        à    ■     0.00
      2  32        à    ■     0.00
      3  32        à    ■     0.00
      4  32        à    ■     0.00
    sum of array elements === 1077477376
    average of array elements === 0.000000
    The median number is 0.000000
    Press any key to continue . . .

    Code:
    #include <stdio.h>
    #include <conio.h>
    int main()
    {
        int number, values, print;
        number = getData();
        values = calculateValues();
        print = printdisplay();
    }
    // Get Data values
    int getData()
    {
      int i, sum = 0, n;
      float avg;
      int a[5];
    
      printf("Enter the array elements\n");
    
      for (i = 0; i < 5; i++) 
      {
        if (scanf("%d", &a[i]) != 1)
          break;
          }  
              return(a[i]);
    }
    int calculateValues()
    {
        double median = 0;
        float avg;
       int n;
       int sum;
       int i;
       int a[5];
       n = i;
    
      for (i = 0; i < 5; i++)
      {
          // Compute the sum of array
       sum=sum+a[i];
       // Compute the average of array
       avg=(float)sum/i;
        median = a[i];
    }
      return 0;
      }
      
    int printdisplay()
    {
        double median = 0;
        int sum;
        float avg;
        int i;
    // Display the array  
        printf(" Index  Item \n");
    for (i = 0; i < 5; i++)
        printf("%3d%4d%9.2c%5c%9.2f\n", i, ' '); 
        // Display the results of the array
     printf("sum of array elements === %d\n", sum);
     printf("average of array elements === %f\n", avg);
     printf("The median number is %f\n", median);
     system("Pause");
    }

  2. #2
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    Toronto, Canada
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    You need to give calculateValues() and printdisplay() access to the array. You can pass the array as a parameter or define it globally.

  3. #3
    Gawking at stupidity
    Join Date
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    Location
    Oregon, USA
    Posts
    3,218
    Code:
    int getData()
    {
      int i, sum = 0, n;
      float avg;
      int a[5];
    
      printf("Enter the array elements\n");
    
      for (i = 0; i < 5; i++) 
      {
        if (scanf("%d", &a[i]) != 1)
          break;
          }  
              return(a[i]);
    }
    You're reading in all the values correctly, but then you're returning a[5], which: 1) Is out of bounds of the array, and 2) Even if it were in bounds, it would only be a single number. You want to return the entire array instead.

    The easiest way to do this (unless you want to do dynamic memory allocation, which you don't), is to declare an array in main() and then pass the array to your getData() function which would then fill it. You don't even need a return value. The prototype would look like this: void getData(int numbers[]);
    If you understand what you're doing, you're not learning anything.

  4. #4
    Registered User
    Join Date
    Feb 2011
    Posts
    21

    New code

    Rewrote the program, now I keep getting invalid lvalue in assignment on line 162 and 163. Also get a error that says 'for' loop initial declaration used outside of C99 mode.

    Code:
    #include <stdio.h>
    #define size 10
    float x[size];
    #define SENTINEL -1.0
    
    
    
     
    int getData(float x[], int arraysize);
    float computeSum(int n, float x[]);
    float computeMean(int n, float sum);
    float computeMedian(int n, float x[]);
    
    void sort(float x[], int n);
    void swap(float * a, float * b);
    
    
    
    
    int main()
    
    {
    
    int n;
    float sum;
    float mean;
    float median;
    int findixsmall;
    
    
    
    n=getData(x, size);
    sum=computeSum(n, x);
    mean=computeMean(n, sum);
    median=computeMedian(n, x);
    findixsmall=computeMedian(n, x, start);
    
    
    for (int a=0;a<n;a++)
    printf("%f\n", x[a]);
    
    printf("Your mean is %f\n", mean);
    printf("Your sum is %f\n", sum);
    }
    
    
    int getData(float x[], int arraysize)     
    
    {
     
        float item;  // Temp cell for each item read
        int counter;    // Count of number of items read
    
        if (arraysize <= 0) return (-2);
    
        counter = 0;   
        // Execute the "priming" or initial read
        printf("Enter the first data item: ");
        scanf ("%f", &item);
        // Repeat until no more data.
        while (item != SENTINEL)
        {
            x[counter] = item;
            counter++;       
            if (counter >= arraysize) return (0); // array full
           // Execute the "update" or next read
            printf("Enter the next data item: ");
            scanf ("%f", &item);
        }
         if (counter == 0) return (-1); // file empty
        else return (counter);
    } // end getData
    
    
    
    float computeSum(int n, float x[])
    {     
    int sum;
    
        sum = 0;
    for (int i = 0; i < n; i++)
     
      {
          
       sum = sum + x[i];
              
      }        
    
    return(sum);
    }
     
    
    
    float computeMean(int n, float sum)
    
    {
      float mean;
     
      mean = sum/n;
    
       
        return (mean);
    }
    
    
     //Find the index of the smallest number in an array x
    //between x[start] and x[n-1].
    
    
    
    float computeMedian(int n, float x[])
    {
    
    void sort(float x[], int n);
        {
       
        int ix//index of smallest item
           
            for(i=0; i<n; i++)
           
            {
                ix=findixsmall(x, i, n);
                swap(&x[ix], &x[i];      
            }
           
        }     
           
           
        ix=findixsmall(x ,start + 1 , n);
       
        int findixsmall(int n,    //IN: the number of items to be compared
                        float x[], //IN: array to be searched
                        int start) //IN: starting search point
       
        {                    
            int n
       
            for(i=start + 1; x<n; i++)
       
            {
                if(x[ixsmall]< x[i])
                ixsmall=i;
            }
           
                return ixsmall;
        }
       
        int i;
        int ixsmall; //index of smallest item
       
        ixsmall=0; //start
       
        swap(& x[ix], & x[0]);
       
        swap(x[start], & x[ixsmall])
       
    void swap
            (float * a, float * b)
        {
            float temp;
            temp= & a;
             & a= & b;
             & b= temp;
           
        } //end swap   
       
            printf("Your median is %f\n", median);
           
    }//end computeMedian

  5. #5
    Registered User
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    Location
    Toronto, Canada
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    I don't see line numbers but I think it's probably complaining about this part... It should be:
    Code:
            temp= *a;
            *a = *b;
            *b = temp;

  6. #6
    Banned
    Join Date
    Aug 2010
    Location
    Ontario Canada
    Posts
    9,547
    1) You cannot nest functions inside functions.

    2) Don't be giving us line numbers unless they're included in your post... Highlight the offending lines with color or boldface... I'm not going to sit here counting 160 lines, I have far better ways of wasting my time.

  7. #7
    Registered User
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    Feb 2011
    Posts
    21
    Thanks nonoob and CommonTater

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