CSE 130   Spring 2010

                                  Lab 6


  PLEASE DO NOT SUBMIT LAB EXERCISES. They are for your practice only.

  1. Two parts of Lab 4

  -    There are two parts to this exercise.  In the first part we  cal-
       culate  mean  of  values stored in one dimensional array. For the
       second part, we print values of a  two  dimensional  array  using
       nested for loops.

  -    Copy lab6.c from this page. Just cut and paste it  in  your  pico
       window.

// lab6.c
// CSE 130 Spring 2010. Lab 6, March 10, 2010
// Sample program for studying arrays.

 #include <stdio.h>

 int main (void)
  {
    float sum, average;
    int i;

  // Declare Array A.

  // Initialize array A.

  // Calculate sum and average.

  // Print sum and average.
  
   return 0;

  }

  2. Actual program.

  a.   First declare an array A of type float and size 6.  For  example,
       float A[6];

  b    Initialize this array by using A[i] = 10.0 + (float)i;  inside  a
       for loop that runs from i = 0 to 5.

  c.   Print array A, from left to right, so you verify what values  are
       in A. Use a for loop and a printf statement inside the loop.

               for (i=0; i < 6; i++)
                 { printf(" %f ", A[i]); }

       Values are 10.0   11.0   12.0   13.0   14.0   15.0

  d.   Write another for loop to obtain sum of all elements of  array  A
       in a variable sum (type float).          sum[i] = sum + A[i];
       Do not forget to initialize sum before the loop.  Calculate aver-
       age = sum/6.0;

  e.   Print sum and average using a printf statement.

  f.   Save your program as lab6.c, compile and execute.

  g.   Average printed should be 12.5.

  3. Part-2

  h.   Copy your program lab6.c to lab62.c.  [   cp  lab6.c  lab62.c   ]
       Here square brackets are not included. 2 means the second version
       of lab6.

  i.   Modify  lab62.c  as  follows.  Make  array  A  two   dimensional.
       A[6][4].  So it will have 6 rows and 4 columns.  Delete all lines
       that compute and print sum as well as average.

  j.   Declare j to be an integer.  Initialize this array  using  values
       based on indices i, j.  Try  A[i][j] = float(i*i + j)/2.0.  Write
       this as two nested for loops. TA will tell you how to do this.

  k.   Now print array A using another pair of  nested  loops.   Do  not
       forget to print \n in the outer loop.  Get help from TA.

  l.   Save your program lab62.c, compile and execute.

  m.   For the 0th row of A, i = 0 and j varies from  0  to  3.  So  the
       first row should be         0.0     0.5     1.0     1.5
       There will be 5 more rows.  Verify that it does print these  rows
       with correct values as shown.

           0.0000    0.5000    1.0000    1.5000
           0.5000    1.0000    1.5000    2.0000
           2.0000    2.5000    3.0000    3.5000
           4.5000    5.0000    5.5000    6.0000
           8.0000    8.5000    9.0000    9.5000
          12.5000   13.0000   13.5000   14.0000


  n.   Extra: Write code for adding all 24 values in the  array.   Print
       the  total.  It  should  be  128.0. Verify if your program prints
       that.