Question

Write a C or C++ program A6p1.c(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). You may refer to testThread.c, testThread2.c, pthread_ex1.c, pthread_ex2.c for examples. Note: Must use pthread to divide the conversion task among the threads.

Answer 1

#include <iostream>
#include <time.h>
#include <stdlib.h>
#include <pthread.h>

using namespace std;
static int a[5][12];
void alterArray(void argument){
for(int i=0;i<5;i++)
{
for(int j=0;j<12;j++)
{
if(a[i][j]%2==0)
{
a[i][j]=a[i][j]+1;
}
else
{
a[i][j]=a[i][j]-1;
}

}

}
}

int main()
{
int n;

cout << "Enter no between 2 and 4" << endl;
cin>> n;
for(int i=0;i<5;i++)
{
for(int j=0;j<12;j++)
{
a[i][j]=rand() % 100;
cout <<a[i][j]<<"\t";
}
cout<<"\n";
}

pthread_t thread1, thread2, thread3, thread4;
int i1,i2,i3,i4;
switch(n)
{
case 2: i1 = pthread_create( &thread1, NULL, alterArray, (void*) "thread 1");
i2 = pthread_create( &thread2, NULL, alterArray, (void*) "thread 2");
pthread_join(thread1,NULL);
pthread_join(thread2,NULL);
break;
case 3: i1 = pthread_create( &thread1, NULL, alterArray, (void*) "thread 1");
i2 = pthread_create( &thread2, NULL, alterArray, (void*) "thread 2");
i3 = pthread_create( &thread3, NULL, alterArray, (void*) "thread 3");
pthread_join(thread1,NULL);
pthread_join(thread2,NULL);
pthread_join(thread3,NULL);
break;
case 4: i1 = pthread_create( &thread1, NULL, alterArray, (void*) "thread 1");
i2 = pthread_create( &thread2, NULL, alterArray, (void*) "thread 2");
i3 = pthread_create( &thread3, NULL, alterArray, (void*) "thread 3");
i4 = pthread_create( &thread4, NULL, alterArray, (void*) "thread 4");
pthread_join(thread1,NULL);
pthread_join(thread2,NULL);
pthread_join(thread3,NULL);
pthread_join(thread4,NULL);
break;
}

for(int i=0;i<5;i++)
{
for(int j=0;j<12;j++)
{
cout<<a[i][j]<<"\t";
}
cout<<"\n";
}
return 0;
}

input Enter no between 2 and 4 3 77 83 86 15 93 35 86 92 49 21 6 2 27 90 59 63 26 40 26 72 36 11 68 6 7 29 82 30 62 23 67 35 29 2 22 58 6 67 56 93 11 42 29 73 21 19 84 37 9 8 24 15 70 13 26 91 80 56 73 62 70 6 81 82 87 76 14 92 34 87 93 48 20 6 3 26 91 58 62 27 41 27 73 37 10 69 6 6 28 83 31 63 22 66 34 28 3 23 59 6 8 66 92 57 10 43 28 72 20 18 85 36 9 25 14 71 12 27 90 81 57 72 63 71 80 7 ... Program finished with exit code o Press ENTER to exit console. LO LO