5.27 1h

Hi

1. What does 2>&1 mean and when is it typically used when added to end of a unix command line ?

&1

# ls -l /mydir >/tmp/out 2>&1

2. Write a shell script which will take a command-line parameter(number) perform a right bit

  shift and print the output on standard output.

Or add 1 to the input number in place of right shift.

>>

i=$((i>>1)) For bit shift

i=$((i+1)) for adding one

3. Write a Makefile to compile myprog.c using standard native C compiler and install/copy the output binary(myprog) under /usr/bin.

myprog: myprog.o

gcc -o myprog -g myprog.o

myprog.o: myprog.c

gcc -g -c -Wall myprog.c

install -o myprog /uer/bin

./myprog >

4. What is/are the difference(s) between malloc, calloc, realloc, vmalloc and kmalloc ?

5. Write a structure definition in C, with following members:

account number              13 characters

social security number      10 characters

name                        64 characters

address                     128 characters

Age                         3 characters

   Feel free to choose your own data type, for each member. For example Age of a person could

   be represented by 1 byte.

stuct obj {

int account_number;

int ssn;

char* name;

char* address;

int age;

} obj;

char name[128] or char *name;

Write a program to calculate factorial of an integer.

n!

#include <stdio>

long long fac(int num) {

if (num<0) return 0;

long long res=1;

int i=1;

for (; i<=num; i++) {

res *=i;

}

return res;

}

int main() {

int num=10;

long long res=fac(num);

printf(“%ld”, res);

return 0;

}

What do the functions atoi() and itoa() do, give an example?

char* name = (char*)malloc(128*sizeof(char));

if(!name) strcpy(name, “123”);

int num=atoi(name);

In C functions, what is the easiest way to pass arrays as arguments ?

void f(int* array);

int main() {

int *array;

f(array);

}

What are register variables? What are advantages of using register variables?

Which is better between insertion, heap sort, and bucket sort, why ?

heap sort O(nlogn)

insertion for array: O(n^2), for list O(n)