Question

1. Write a C or C++ program A6pc(pp) that accepts one command line argument which is an integer n between 2 and 6 inclusive. Generate a string of 60 random upper case English characters and store them somewhere (e.g. in a char array). Use pthread to create n threads to convert the string into a complementary string (‘A’<->’Z’, ‘B’<->’Y’, ‘C’<->’X’, etc). You should divide this conversion task among the n threads as evenly as possible. Print out the string both before and after conversion on two separate lines. Hint: it is dangerous to have printing code in your thread function(s). Note: if you do not use pthread to divide the conversion task among the threads, you may get zero points.
2. Write a C or C++ program A6p2.c(pp) that accepts one command line argument which is an integer n between 2 and 4 inclusive. Generate 60 random integers between 1 and 49 inclusive and store them in a 5 by 12 two dimensional integer array (e.g.,int a[5][12];). Use pthread to create n threads to square all 60 array elements. You should divide this update task among the n threads as evenly as possible. Print the array both before and after the update separately as 5 by 12 matrices. Note: if you do not use pthread to divide the update task among the threads, you may get zero points

The output of the programs should look like this

.

[kwang@talon-transfer-2.local)(~/work/temp/testc/A6new] $ A6p1 2 using 2 threads . original upper case string: CAVZTWKMOQUNAFHFDARXWGZSUHMCHTYJUVKPRWDGMZTNEBUJDLIZTIUNRGPY complementary string: XZEAGDPNLJFMZUSUWZIČDTAHFSNXSGBQFEPKIDWTNAGMVYFQWORAGRFMITKB [kwang@talon-transfer-2.local] [~/work/temp/testc/A6new] $ A6p2 _2 us ing 2 threads. original array : 28 14 23 23 36 3 7 34 42 30 6 23 46 44 14 39 43 29 16 22 39 19 25 15 21 27 25 33 26 4 32 17 11 43 1 8 29 1 30 25 5 49 38 48 42 17 20 updated array: 784 196 529 7 39 34 19 43 43 26 15 16 3 4 529 1296 9 49 1156 1764 900 36 529 2116 1936 196 1521 1849 841 256 484 1521 361 625 225 441 729 1089 625 625 676 81 16 1024 289 121 1849 2304 1 64 841 121 900 625 25 2401 1444 1764 289 400 361 49 1849 1849 676 225 256 C 1521 16 1156

Answer 1

############ part 1

#include<stdio.h>
#include<iostream>
#include<stdlib.h> //for rand()
#include <pthread.h> //for pthread
#include<time.h>
using namespace std;

char arr[60];
int mark=0;
int size=0;

void swap(int start, int endd)
{
int ii;
int j;
for(ii=start;ii<=endd;ii++)
{
j=int(arr[ii]);
j=90-(j-65);
arr[ii]=char(j);
}
}
void *fun(void *thread_id)
{

swap(mark,mark+size-1);
mark=mark+size;

pthread_exit(NULL);
}

int main()
{
int n,i,num;
cout << "Enter any number between 2 and 6 inclusive: ";
cin>>n;
if(n<2 || n>6)
{
cout<<"Invalid Input";
exit(0);
}
cout<<"Number of threads used: "<<n;
cout<<"\n";
size=60/n; // number of elements of array "char[arr]" to be handled by each thread
srand(time(0));
for(i=0;i<60;i++)
{
num=(rand() % 25)+65; // ASCII value of 'A' to 'Z' is 65 to 90
arr[i]=char(num);
}

cout<<"Original Array: ";
for(i=0;i<60;i++)
{
cout<<arr[i]<<" ";

}
pthread_t thread[n];
int x;
for( i = 0; i < n; i++ )
{
x = pthread_create(&thread[i], NULL, fun, (void *)i);

if (x)
{
cout << "Error: Thread could not be created," << x << endl;
exit(-1);
}
}

cout<<"\n";
cout<<"\n";
cout<<"Modified Array: ";
for(i=0;i<60;i++)
{
cout<<arr[i]<<" ";

}
pthread_exit(NULL);

return 0;
}

############################### part 2

#include<stdio.h>
#include<iostream>
#include<stdlib.h> //for rand()
#include <pthread.h> //for pthread
#include<time.h>
using namespace std;

int arr[5][12];
int arr2[60];
int mark=0;
int size=0;

void fun2(int start, int endd)
{
int ii;
int j;
for(ii=start;ii<=endd;ii++)
{
arr2[ii]=arr2[ii]*arr2[ii];
}
}
void *fun(void *thread_id)
{

fun2(mark,mark+size-1);
mark=mark+size;

pthread_exit(NULL);
}

int main()
{
int n,i,y,num,a,b;
cout << "Enter any number between 2 and 4 inclusive: ";
cin>>n;
if(n<2 || n>4)
{
cout<<"Invalid Input";
exit(0);
}
size=60/n;
srand(time(0));
for(i=0;i<60;i++)
{
num=(rand() % 49); // Random number generation b/w 1-49
a=int(i/12);
b=i-(12*a);
arr[a][b]=num;
arr2[i]=num;
}

cout<<"Original Array: ";
for(i=0;i<6;i++)
{
for(y=0;y<12;y++)
{
cout<<arr[i][y]<<" ";
}
}

pthread_t thread[n];
int x;
for( i = 0; i < n; i++ )
{
x = pthread_create(&thread[i], NULL, fun, (void *)i);

if (x)
{
cout << "Error: Thread could not be created," << x << endl;
exit(-1);
}
}

cout<<"\n";
cout<<"\n";
for(i=0;i<60;i++)
{

a=int(i/12);
b=i-(12*a);
arr[a][b]=arr2[i];
}

cout<<"Modified Array: ";
for(i=0;i<6;i++)
{
for(y=0;y<12;y++)
{
cout<<arr[i][y]<<" ";
}
}
pthread_exit(NULL);

return 0;
}