Lab for Week 0  (Jan 3-5, 2011)
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You will learn to operate on computers in this lab.

1. Basic commands as discussed in the class:

* Login and logout
* Opening a terminal
* mkdir, rmdir, cd, pwd
* touch, cp, mv, rm, ln  
* ls, more, cat, head, tail, wc, diff
* chmod, passwd 

2. Using Vi editor: create a file, save it and exit.

3. Create a file named as "firstProgram.c" using Vi and type-in the C 
program below. 

#include <stdio.h>
int main() {
        int a = 4, i = 5;
        int b, c, j;

        c = (b = a % 5) - (a = 1);
        printf("%d \n" , c);

        j = i++ * 2 -  ++i * 2;
        printf("%d %d\n" , j, i);
}

Use the following command to create the executable:  
gcc -o myFirst firstProgram.c
Then execute the program.

4. Create 3 different files: (i) "subtract_multiSrc.c",
(ii) "multiply_multiSrc.c" and (iii) "multiSrc.c" for the following
three programs.  

(i)

int subtract(int a, int b) {
    return a-b;
}

(ii) 

int multiply(int a, int b) {
    return a*b;
}

(iii)

#include <stdio.h>

extern subtract(int a, int b);
extern multiply(int a, int b);

int main() {
   int a = 10, b = 5;
   int c = subtract(a,b), d = multiply(a,b);
   printf("results are : %d and %d\n", c, d);
}

Now compile all three files together by using the following command

gcc add_multiSrc.c multiply_multiSrc.c multisrc.c

It will create a file "a.out" in your current directory. Execute this
file by issuing "./a.out" command.