Question

Learn the example C program in Folio consisting of three files (a.c, a.h, main.c) and complete this exercise. You need to understand function, pointer and the selection sort algorithm. Write a C program that consists of three files mysort.h, mysort.c and myMain.c. Below is the mysort.h prototype

#include <stdlib.h>

#include <stdio.h>

void generateNums(int *myarr, int len);

void sortNums(int *myarr, int len);

• mysort.h must contain only the function declarations (prototypes) listed above
• generateNums function should generate len random integers in the range 0~99 inclusive (use rand function in <stdlib.h>) in the supplied array myarr. Its definition should be in mysort.c.
• sortNums function should sort the len integers at myarr into ascending order using selection sort algorithm. Its definition should be in mysort.c. Note that the caller of sortNums and generateNums should pass valid pointers myarr to them.

1. In myMain.c you need to write your main function that calls the two functions in mysort.h to generate N random integers in the range 0~99 inclusive and then print out the generated unsorted random numbers in one line with suitable separators between them and the sorted N numbers in another line. Your program should get N (which represents the number of random integers you will generate and sort) from the first command line argument (i.e. argv[1]) of this C program (you can use the atoi function; see example code LeapYear_cmdline.c). Submit all three source files. (37 pts)
2. Submit a makefile to compile your program. Be aware of the possible file name issue regarding Folio complaint. See the last slide of 3_Pointers_Functions.pptx for details. Make sure you have tested that your makefile works. (3 pts)

2. (40 pts) You need to understand array, pointer and pointer arithmetic to complete this exercise. And you should be able to figure out the answers without actually compiling and running the program. You may recall problem 4 of assignment 2.

#include <stdio.h>

int main(int argc, char *argv[])

{

     char a, *pc, c[9];

     int i, *pk, k[9];

     a='z';

     pc=&(c[8]);

     pk=&(k[0]);

     for (i=0; i<9; i++)

    {

          *pc=a-(char)i;

          pc--;

          *pk=(int)a-i;

          pk++;

         }

                  return 0;

}//end of main

1. Write out the memory map for the above C code in the following table. For array variables, list the address range for the entire array. Assume the memory address starts from 100, that is, the address for a is 100. Suppose sizeof(char)=1, sizeof(int)=4 and the size of a memory address (a pointer) is 8 bytes. You may assume there is no gap in memory between the variables. (18 pts)

Variable	Start address	End address
a
pc
c
i
pk
k

2. Additionally, show values of the variables in the following table at the end of execution of the for loop before the main function returns. (For the two array variables c and k, list the contents of all array elements.) (18 pts)

Variable	Value
a
pc	Use an expression involving c to represent pc’s value
c	list the contents of the entire array
i
pk	Use an expression involving k to represent pk’s value
k	list the contents of the entire array

3. True or false? pc and pk have the same value just before return. (2 pts)
4. True or false? The two array c and k contain the same integral values just before return. (2 pts)

Answer 1

Program :

File mysort.h contents:

#include<stdio.h> // header file declarations
#include<stdlib.h>
void generateNums(int *myarr, int len); // function prototype declarations
void sortNums(int *myarr, int len);

File mysort.c contents:

#include<stdio.h> // header file declarations

#include<stdlib.h>

#include<time.h>

#include "mysort.h" // importing the mysort function prototype file

void generateNums(int *myarr, int len) {

srand(time(NULL));

for (int i = 0; i < len; i++)

myarr[i] = rand() % (100 + 1 - 0) + 0; // generating random numbers from 0 to N using rand function

}

void sortNums(int *myarr, int len) {

int pos, j, swap;

for (int i = 0; i < len - 1; i++) {

pos = i;

for (j = i + 1; j < len; j++) {

if (myarr[pos] > myarr[j])

pos = j; // applying the selection sort algorithm

}

if (pos != i) {

swap = myarr[i]; // swapping the two integers for correct sorting

myarr[i] = myarr[pos];

myarr[pos] = swap;

}

}

}

File myMain.c contents:

#include<stdio.h> // header file declarations

#include<stdlib.h>

#include "mysort.h" // importing the mysort function prototype and declaration files

#include "mysort.c"

int main(int argc, char **argv) {

int N = atoi(argv[1]); // taking the number of random numbers to be generated as command line argument

int myarr[N], i;

generateNums(myarr, N); // generating random number from 0 to N

printf("\nThe numbers before sorting are: ");

for (i = 0; i < N; i++)

printf("%d ", myarr[i]); // printing the unsorted random numbers in one line

printf("\n");

sortNums(myarr, N); // sorting the unsorted list of numbers

printf("\nThe numbers after sorting are: ");

for (i = 0; i < N; i++)

printf("%d ", myarr[i]); // printing the sorted random numbers in next line

printf("\n");

return 0;

}

E a (0:22, 96%) С mysort.h )-gedit 40 Tue May 29 2018 07:27:42 save mysort.h myMain.c mysort.c #include«stdio.h> #include«stdlib.h> // header file declarations votd generateNuns(int *nyarr, int len) // functton prototype declarattons votd sortNuns(int *myarr, int len):l c/C++/ObjC HeaderTab Width: 8Ln 4, Col 36 INS

E R A mysort.c gedit (0:18, 96%) CE q) Tue May 29 201 8 07:33:14 Open Save #include«stdio.h> #include«stdlib.h> #include« tine, h> // header file declarations #include "nysort.h" // inporting the Mysort function prototype file void generateNuns (int *nyarr, int len) [ srand (time(NULL)); nyarr[t] = rand() % (100 + 1-0) + e; // generating randon numbers fron θ to N using rand function void sortNums (int *myarr, int len) int pos, J, swap; for (inti-e; <len 1; i++) if (nyarr[pos] > myarr[]) posj // applying the selection sort algorithp if (pos -i) swap myarr[i] / swapping the two integers for correct sorting myarr[i] nyarr[pos]; myarr[pos] Swap; C Tab Width: 8 Ln 24, Col 2 INS ▼

E R A myMain.c ) -gedit (0:22, 96%) CE q) Tue May 29 201807:27:47 Open ▼ Save mysort.h myMain.c mysort.c #include«stdio.h> #include«stdlib.h> // header file declarations #include "nysort.h" // ǐnporting the nysort function prototype and declaration files #include "Mysort.c" int main (int argc, char**argv) [ intN atoi(argv[1]) //taking the number of random numbers to be generated as command line argument int myarr[N], t; generateNums (myarr, N); printf(nThe numbers before sorting are:); // generating randon nunber fron θ to N printf("%d ", nya r r [1]); printf(In); sortNums (myarr, N); sorting the unsorted list of numbers printf(nThe numbers after sorting are:"; // printing the unsorted random numbers in one line printf("%d printf( In"); return ; ", nyarr[1]); // printing the sorted random numbers in next line C Tab Width: 8 Ln 19, Col2 INS
output

2.

ㄧ 宋小 . sourav@sourav-HP-Pavilion: sourav@sourav-HP-Pavilion$ vim mysort.h sourav@sourav-HP-Pavilion- vim mysort.c sourav@sourav-HP-Pavilion:$ vim myMain.c sourav@sourav-HP-Pavilion-$ gcc myMain.c sourav@sourav-HP-Pavilion:/a.out 5 审 (0:18, 96%) CE 빠q) Tue May 29 201807:33:24 The numbers before sorting are: 54 44 23 18 9 The numbers after sorting are: 9 18 23 44 54 sourav@sourav-HP-Pavilion:-s /a.out 7 The numbers before sorting are: 73 19 46 63 38 51 73 The numbers after sorting are: 19 38 46 51 63 73 73 sourav@sourav-HP-Pavilion:$ ./a.out 10 The numbers before sorting are: 93 17 27 17 90 60 59 97 68 32 The numbers after sorting are: 17 17 27 32 59 60 68 90 93 97 sourav@sourav-HP-Pavilion$

Varlable Start Address End Address 100 100 101 109 pc 110 118 119 136 169 Values of the variables Varlable Value cli] = a-Chari, for j starts from 7 until 0 pc kl-i+5 13 Bytes in total code allocates for the variales is: 65 Bytes