SE250:lab-2:aomr001

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The lab task for todays lab was to find more and explore pointers and different data structures. I have done a number of different tasks and compiled and ran these on 2 different machines, on a windows operating system (x32) and on a LINUX machine (x64) to see what effect that would have on my results.


task1

for task 1 .. my code was : 

char *ip;
    double *ip1;
    short *ip2;
    float *ip3;
    long *ip4;
    printf("ip = %d\nip1 = %d\nip2 = %d\nip3 = %d\nip4 = %d\n",
	   sizeof(ip),sizeof(ip1),sizeof(ip2),sizeof(ip3),sizeof(ip4));

and the output on the vista os was: 

ip = 4
ip1 = 4
ip2 = 4
ip3 = 4
ip4 = 4

while the output on the linux machine was: 

ip = 4
ip1 = 4
ip2 = 4
ip3 = 4
ip4 = 4

task2

a) 

printf("address of x= %p, address of y= %p, difference= %ld\n",&x, &y ,(long)(&x - &y));

output on windows: 

address of x= 0x22ccc4, address of y= 0x22ccc0, difference= 1

ouput on linux: 

&x = 0xfff0b9dc, &y = 0xfff0b9d8, diff = 1


i was asked to do a little editing to the code: 

printf("address of x= %p, address of y= %p, difference= %ld\n",&x, &y  ,((long)&x -(long)&y));


output on windows: 

address of x= 0x22ccc4, address of y= 0x22ccc0, difference= 4

output on LINUX: 

&x = 0xfff0b9dc, &y = 0xfff0b9d8, diff = 4


task3

printf("sizeof arr = %d\n", sizeof(arr));

output on windows: 

sizeof arr = 4

output on LINUX: 

size of arr = 4


c) 

printf("address of arr  = %p",&arr);

output on WINDOWS: 

address of arr = 2280640


output on LINUX: 

address of arr = 0xffc1d9d4

d) 

printf("arr+4 = %d, &arr[4]= %d", arr+4,&arr[4]);

output on LINUX: 

arr+4 = -2225704, &arr[4]= -2225704

e) 

for (i =0; i < 10; i++){
    arr[i];
    printf("diff &x - &y  = %d\n",(long)(&x - &y));

output on WINDOWS: 

diff btwn &x and &y whn arr[0] = 8
diff btwn &x and &y whn arr[1] = 2
diff btwn &x and &y whn arr[2] = 2
diff btwn &x and &y whn arr[3] = 8
diff btwn &x and &y whn arr[4] = 2
diff btwn &x and &y whn arr[5] = 8
diff btwn &x and &y whn arr[6] = 8
diff btwn &x and &y whn arr[7] = 8
diff btwn &x and &y whn arr[8] = 4
diff btwn &x and &y whn arr[9] = 8
diff btwn &x and &y whn arr[10] = 8


output on LINUX: 

diff &x - &y  = 1
diff &x - &y  = 1
diff &x - &y  = 1
diff &x - &y  = 1
diff &x - &y  = 1
diff &x - &y  = 1
diff &x - &y  = 1
diff &x - &y  = 1
diff &x - &y  = 1
diff &x - &y  = 1


f) 

  printf("x = %d, y = %d",x,y);


output on WINDOWS: 

x = 10, y = 0


output on LINUX: 

x = 167772160, y = 0

task4

X and y as global variables
printf("&x = %p, &y = %p, diff = %ld\n",&x,&y, (long)(&x - &y));
printf("&x = %p, &y = %p, diff = %ld\n",&x,&y, (long)&x - (long)&y);
printf(“sizeof(arr) = &d”, sizeof(arr));
printf("address of arr = %d",&arr);
printf("address of arr+4  = %d",&arr+4);
printf("address of arr [4]= %d",&arr[4]);

output on WINDOWS: 

&x = 0x403030, &y = 0x403020, diff = 4
&x = 0x403030, &y = 0x403020, diff = 16
sizeof(arr) = 4
address of arr = 4206640
address of arr+4 = 4206656
address of arr[4] = 4206644

diff btwn &x and &y whn arr[0] = 8
btwn &x and &y whn arr[1] = 8
diff btwn &x and &y whn arr[2] = 8
diff btwn &x and &y whn arr[3] = 8
diff btwn &x and &y whn arr[4] = 8
diff btwn &x and &y whn arr[5] = 8
diff btwn &x and &y whn arr[6] = 8
diff btwn &x and &y whn arr[7] = 8
diff btwn &x and &y whn arr[8] = 8
diff btwn &x and &y whn arr[9] = 8
diff btwn &x and &y whn arr[10] = 8


task5

int *p1, *p2;
{ int q; p1 = &q; }
{ int r; p2 = &r; }

output on WINDOWS: 

p1 = 2280636 , p2 = 2280632

output on LINUX: 

p1 = -7644716, p2 = -7644716


task6

sp = local str( );
printf( ”sp = %p(%s)\n”, sp, sp );
sp = local str( );
local str2( );
printf( ”sp = %p(%s)\n”, sp, sp );
sp = static str( );
local str2( );
printf( ”sp = %p(%s)\n”, sp, sp );
sp = malloc str( );
local str2( );
printf( ”sp = %p(%s)\n”, sp, sp );

output on WINDOWS: 

sp = 0x22cc90(456)
sp = 0x22cc90(efg)
sp = 0x402000(tuvwxyz)
sp = 0x10401a0(hijklmn)

output on LINUX: 

sp = 0xffbc29a4(þîÐ)
sp = 0xffbc29a4(abcdefg)
sp = 0x10010cd4(tuvwxyz)
sp = 0x10011008(hijklmn)



strcpy( sp, ”XXXXXXX” );
printf( ”sp X’d = %p(%s)\n”, sp, sp );


output on WINDOWS: 

sp = 0x22cc90(456)
sp X'd = 0x22cc90(-0@)
sp = 0x22cc90(efg)
sp X'd = 0x22cc90(-0@)
sp = 0x402000(tuvwxyz)
sp X'd = 0x402000(XXXXXXX)
sp = 0xda01a0(hijklmn)
sp X'd = 0xda01a0(XXXXXXX)

output on LINUX: 

sp = 0xffb0f9a4(þîÐ)
sp X'd = 0xffb0f9a4(XXXXXXX)
sp = 0xffb0f9a4(abcdefg)
sp X'd = 0xffb0f9a4(XXXXXXX)
sp = 0x10010dc0(tuvwxyz)
sp X'd = 0x10010dc0(XXXXXXX)
sp = 0x10011008(hijklmn)
sp X'd = 0x10011008(XXXXXXX)


task7

output on WINDOWS: 

&my_struct = 0x0
offsets:
my_char: 0
my_short: -2
my_int: -4
my_long: -8
my_float: -12
my_double: -16


output on LINUX: 

&my_struct = 0xffe879c0
offsets:
my_char: 0
my_short: -2
my_int: -4
my_long: -8
my_float: -12
my_double: -16


task8

output on WINDOWS: 

&my_struct = 0x0
offsets:
my_char: 0
my_short: 0
my_int: 0
my_long: 0
my_float: 0
my_double: 0

ouput on LINUX: 

&my_struct = 0xffafe9d8
offsets:
my_char: 0
my_short: 0
my_int: 0
my_long: 0
my_float: 0
my_double: 0


task9

output on WINDOWS: 

sp1 address: 0x22ccc4
sp2 address: 0x22ccc0
sp3 address: 0x22ccbc


output on LINUX: 

sp1 address: 0xffb5b9dc
sp2 address: 0xffb5b9d8
sp3 address: 0xffb5b9d4


task10

output on windows: 

local_str = 0x401050


ouput on LINUX: 

local_str = 0x100004dc
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