Thread: Last row in array problem

The last row in this array of values is not coming out right.
Do you mind taking a look and letting me know what I'm missing?
Here is a screen cap of my output:



All of the other rows look fine.
This has been bugging me for a few hours, so any help will be awesome!

Code:

/* Header Files */
#include <stdio.h>
#include <math.h>


/*defined constants*/


#define max_column  5
#define max_row     5
#define Y            .05
#define pi          3.14
#define d_zeta       .05
#define d_k     50000
/*Start of main function*/
int main(void)
{


   /* declarations: */
    char c;
    double zeta = .4, k, alpha, alpha_n, r, X, amp[max_column][max_row];
    int column = 0, row, j, i;
   /*Statements that perform the desired task*/
    while(zeta <= .6)
    {
        row = 0;
        k = 300000;
        while(k <= 500000)
        {
            alpha = (2*pi*1.08);
            alpha_n = sqrt(k / 1200.0);
            r = alpha / alpha_n;
            amp[column][row] = Y * sqrt((1 + ((2 * zeta * r) * (2 * zeta * r))) / (((1 - (r * r)) * (1 - (r * r)) + (( 2 * zeta * r) * (2 * zeta * r)))));
            
            row ++;
            k = k + d_k;
        }
        zeta = zeta + d_zeta;
        column ++;
    }


    k = 300000;
   /*Printing the results*/
    printf("
 Amplitude of Vibrations at 20 kph

");


    printf("K\Damping Ratio|    ");
    zeta = .4;
    while(zeta < .61)
    {
        printf("%0.2f    ", zeta);
        zeta += d_zeta;
    }
    printf("
________________________________________________________
");
    
        for(row = 0; row < max_row; row++)
        {
            /*Print row label*/
            
            printf("   %6.0f      |    ", k);
            k += d_k;
            /*Print the data*/
            for( column = 0; column < max_column; column++)
            {
                printf("%0.4f    ", amp[row][column]); 
            }
            printf("
");
            
        }


   /*This keeps the window open*/
   printf("

Press enter to q to quit.
");
   do{ 
       c = getchar();
   }while( c != 'q' );


   /*end the program*/
   return 0;
}

Here you are inputting into 4*5 array

Code:

amp[column][row] = Y * sqrt((1 + ((2 * zeta * r) * (2 * zeta * r))) / (((1 - (r * r)) * (1 - (r * r)) + (( 2 * zeta * r) * (2 * zeta * r)))));

Here you are displaying 5*5 array

Code:

 for(row = 0; row < max_row; row++)
        {
            /*Print row label*/

            printf("   %6.0f      |    ", k);
            k += d_k;
            /*Print the data*/
            for( column = 0; column < max_column; column++)
            {
                printf("%0.4f    ", amp[row][column]); 
            }
            printf("
");
             

Change max_row to 4... Then its fine..

Originally Posted by hk_mp5kpdw

Get rid of zeta from the code.

Thanks a lot, that did the trick. Makes total since in retrospect.

Originally Posted by hk_mp5kpdw

The getchar function returns an int, not a char

[/QUOTE]

My instructor gave us a template to use on our programs, and it includes that line.
I will recognize that it is not good programming practice in the future.