CSC231 Optional Homework 9 2017

--D. Thiebaut (talk) 11:10, 22 April 2017 (EDT)

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Problem 1: C Functions

Write a C program that contains only C functions. The functions will be called by an external main program. This is very similar to the the last homework assignment, except then it was done in assembly.

Functions

You have to write 3 functions: getMin(), zap() and merge().

getMin()

Receives 3 ints as parameters and returns the smallest.

Example

  printf( "Min of -10, 1, 10 = %d\n", getMin( -10, 1, 10 ) );
  printf( "Min of -10, 1, 10, -20, 2 = %d\n", getMin( getMin( -10, 1, 10 ), -20, 2 ) );
  // output:
  //  Min of -10, 1, 10 = -10
  //  Min of -10, 1, 10, -20, 2 = -20

zap()

Receives two strings as parameters and modifies the first one by finding the first

string in it, and replacing it with dashes.

Example

  char s1[] = "Mississippi Burning";
  char s2[] = "Mississippi Burning";

  //--- test zap ---
  printf( "s1 = %s\n", s1 );
  zap( s1, "ss" );
  printf( "zap(s1) = %s\n", s1 );

  printf( "s2 = %s\n", s2 );
  zap( s2, "tt" );
  printf( "zap(s2) = %s\n", s2 );
 
  // output:
  // s1 = Mississippi Burning
  // zap(s1) = Mi--issippi Burning 
  // s2 = Mississippi Burning
  // zap(s2) = Mississippi Burning

merge()

receives 3 arrays of ints. The first two have dimension 5, each, and are sorted. The third one is of dimension 10, and contains random information, i.e. it is not initialized. Merge() takes the ints from both arrays of dimension 5 and merges them into the third array, keeping the ints sorted. You may assume that the first two arrays will always have dimension 5, and the third one will always have dimension 10.

Example

  int A[] = { 1, 2, 3, 10, 11 };
  int B[] = { 4, 5, 12, 13, 15 };
  int C[10];

  merge( A, B, C );
  for ( i=0; i<10 && A[i]!=-1; i++ )
    printf( "%d, ", C[i] );
  printf( "\n" );
  // output:
  // 1, 2, 3, 4, 5, 10, 11, 12, 13, 15,

Merging in Python

For reference, here is how merge would work in Python:

from __future__ import print_function

def merge( A, B, C ):
    """
    merges 2 arrays into a 3rd one.  The dimensions of the arrays can be 
    any valid integer.  C must be a mutable list.
    """
    i = 0
    j = 0
    k = 0
    while i<len(A) and j<len(B):
        if A[i] < B[j]:
            C.append( A[i] )
            i += 1
        else:
            C.append( B[j] )
            j += 1
        if i >= len( A) or j >= len( B ):
            break
    while i < len( A ):
        C.append( A[i] )
        i += 1
    while j < len( B ):
        C.append( B[j] )
        j += 1
 
def main():   
    A = [1, 3, 10, 20, 30 ]
    B = [2, 3, 4, 5, 100 ]
    C = []
    merge( A, B, C )
    print( "A = ", A )
    print( "B = ", B )
    print( "C = ", C )

main()

# output
# A =  [1, 3, 10, 20, 30, 31]
# B =  [2, 3, 4, 5, 100]
# C =  [1, 2, 3, 3, 4, 5, 10, 20, 30, 31, 100]