SE250:lab-2:asin185
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Lab 2
Intro
For this lab we must generate results from both our local computers and the the Linux server. Then compare these results retrieved. This is done so that the different memory allocation can be shown for different C compilers.
Task 1
#include <stdio.h>
int main () {
int *ip;
double *ip2;
float *ip3;
long *ip4;
short *ip5;
printf("int p = %d\ndouble p = %ld\nfloat p = %ld\nlong p = %ld\nshort p = %ld\n", sizeof(ip2) , sizeof(ip), sizeof(ip3), sizeof(ip4), sizeof(ip5));
return 0;
}
Int p = 4 Double p = 4 Float p = 4 Long p = 4 Short p = 4
Task 2
#include <stdio.h>
int main (){
int x;
int y;
printf("&x = %p, &y = %p, diff = %ld\n", &x, &y, (long)&x - (long)&y);
printf("&x = %p, &y = %p, diff = %ld\n", &x, &y, (long)(&x - &y));
return 0;
}
&x = 0x22ccc4, &y = 0x22ccc0, diff = 4 &x = 0x22ccc4, &y = 0x22ccc0, diff = 1
Task 3
#include <stdio.h>
int main (){
int x = 0;
char arr[ 4 ];
arr[ 4 ] = 10;
int y = 0;
printf("size of array = %d\n", sizeof(arr));
printf("&arr = %p\n", &arr );
printf("value &arr = %d\n", arr );
printf("value &arr + 4 = %d\n", arr+4 );
printf("value &arr[4] = %d\n", &arr[4] );
printf("\n");
printf("value of x = %d\nvalue of y = %d\n", x, y);
printf("\n");
printf("&x = %p, &y = %p, diff = %ld\n", &x, &y, (long)(&x - &y));
return 0;
}
size of array = 4 &arr = 0x22ccc0 value &arr = 2280640 value &arr + 4 = 2280644 value &arr[4] = 2280644 &x = 0x22ccbc, &y = 0x22cc9c, diff = 8 0 &x = 0x22ccc4, &y = 0x22ccbc, diff = 2 1 &x = 0x22ccc4, &y = 0x22ccbc, diff = 2 2 &x = 0x22ccbc, &y = 0x22cc9c, diff = 8 3 &x = 0x22ccc4, &y = 0x22ccbc, diff = 2 4 &x = 0x22ccbc, &y = 0x22cc9c, diff = 8 5 &x = 0x22ccbc, &y = 0x22cc9c, diff = 8 6 &x = 0x22ccbc, &y = 0x22cc9c, diff = 8 7 &x = 0x22ccc4, &y = 0x22ccb4, diff = 4 8 &x = 0x22ccbc, &y = 0x22cc9c, diff = 8 9 &x = 0x22ccbc, &y = 0x22cc9c, diff = 8 10 value of x = 10 value of y = 0
Task 4
4.1
#include <stdio.h>
int x;
int y;
int main (){
printf("&x = %p, &y = %p, diff = %ld\n", &x, &y, (long)(&x - &y));
return 0;
}
&x = 0x403030, &y = 0x403020, diff = 4 &x = 0x403030, &y = 0x403020, diff = 16
4.2
#include <stdio.h>
int x;
int y;
int main (){
char arr[ 4 ];
arr[ 4 ] = 10;
printf("size of array = %d\n", sizeof(arr));
printf("&arr = %p\n", &arr );
printf("value &arr = %d\n", arr );
printf("value &arr + 4 = %d\n", arr+4 );
printf("value &arr[4] = %d\n", &arr[4] );
return 0;
}
size of array = 0 &arr = 0x22ccb0 value &arr = 2280624 value &arr + 4 = 2280628 value &arr[4] = 2280628 &x = 0x403030, &y = 0x403020, diff = 4 0 &x = 0x403030, &y = 0x403020, diff = 4 1 &x = 0x403030, &y = 0x403020, diff = 4 2 &x = 0x403030, &y = 0x403020, diff = 4 3 &x = 0x403030, &y = 0x403020, diff = 4 4 &x = 0x403030, &y = 0x403020, diff = 4 5 &x = 0x403030, &y = 0x403020, diff = 4 6 &x = 0x403030, &y = 0x403020, diff = 4 7 &x = 0x403030, &y = 0x403020, diff = 4 8 &x = 0x403030, &y = 0x403020, diff = 4 9 &x = 0x403030, &y = 0x403020, diff = 4 10 value of x = 0 value of y = 0
Task 5
#include <stdio.h>
int x;
int y;
int main (){
int *p1, *p2;
{ int q; p1 = &q; }
{ int r; p2 = &r; }
printf("value of p1 = %d\nvalue of p2 = %d", p1, p2);
return 0;
value of p1 = 2280636 value of p2 = 2280632
Task 6
#include <stdio.h>
char *local_str( ) {
char s[8] = "0123456";
return s;
}
char *local_str2( ) {
char s[8] = "abcdefg";
return s;
}
char *static_str( ) {
static char s[8] = "tuvwxyz";
return s;
}
char *malloc_str( ) {
char *s = malloc( 8 );
strcpy( s, "hijklmn" );
return s;
}
int main (void) {
char *sp;
sp = local_str( );
printf( "sp = %p(%s)\n", sp, sp );
strcpy( sp, ”XXXXXXX” );
printf( ”sp X’d = %p(%s)\n”, sp, sp );
sp = local_str( );
local_str2( );
printf( "sp = %p(%s)\n", sp, sp );
strcpy( sp, ”XXXXXXX” );
printf( ”sp X’d = %p(%s)\n”, sp, sp );
sp = static_str( );
local_str2( );
printf( "sp = %p(%s)\n", sp, sp );
strcpy( sp, ”XXXXXXX” );
printf( ”sp X’d = %p(%s)\n”, sp, sp );
sp = malloc_str( );
local_str2( );
printf( "sp = %p(%s)\n", sp, sp );
strcpy( sp, ”XXXXXXX” );
printf( ”sp X’d = %p(%s)\n”, sp, sp );
return 0;
}
6.1
sp = 0x22cca0(456) sp = 0x22cca0(efg) sp = 0x402000(tuvwxyz) sp = 0x670178(hijklmn)
6.2
sp = 0x22cca0(456)
sp X'd = 0x22cca0('1@)
sp = 0x22cca0(efg)
sp X'd = 0x22cca0('1@)
sp = 0x402000(tuvwxyz)
sp X'd = 0x402000(XXXXXXX)
sp = 0x670178(hijklmn)
sp X'd = 0x670178(XXXXXXX)
Task 7
struct {
char my char;
short my short;
int my int;
long my long;
float my float;
double my double;
} my struct;
int main(void){
printf( ”&my struct = %p\n”, my struct );
printf( ”offsets:\n”
”my char: %ld\n”
”my short: %ld\n”
”my int: %ld\n”
”my long: %ld\n”
”my float: %ld\n”
”my double: %ld\n”,
(long)&my struct − (long)&my struct.my char,
(long)&my struct − (long)&my struct.my short,
(long)&my struct − (long)&my struct.my int,
(long)&my struct − (long)&my struct.my long,
(long)&my struct − (long)&my struct.my float,
(long)&my struct − (long)&my struct.my double );
return 0;
}
&my_struct = 0x404030 offsets: my_char: 0 my_short: -2 my_int: -4 my_long: -8 my_float: -12 my_double: -16
Task 8
union {
char my_char;
short my_short;
int my_int;
long my_long;
float my_float;
double my_double;
} my_union;
int main (void) {
printf( "&my_union = %p\n", &my_union );
printf( "offsets:\n"
"my_char: %ld\n"
"my_short: %ld\n"
"my_int: %ld\n"
"my_long: %ld\n"
"my_float: %ld\n"
"my_double: %ld\n",
(long)&my_union - (long)&my_union.my_char,
(long)&my_union - (long)&my_union.my_short,
(long)&my_union - (long)&my_union.my_int,
(long)&my_union - (long)&my_union.my_long,
(long)&my_union - (long)&my_union.my_float,
(long)&my_union - (long)&my_union.my_double );
return 0;
}
&my_union = 0x404050 offsets: my_char: 0 my_short: 0 my_int: 0 my_long: 0 my_float: 0 my_double: 0
Task 9
int main(void) {
char *sp1, *sp2, *sp3;
sp1 = malloc(10);
sp2 = malloc(10);
printf("sp1 = %p sp2 = %p\n", sp1, sp2);
free(sp1);
sp3 = malloc(10);
printf("sp1 = %p sp2 = %p sp3 = %p\n", sp1, sp2, sp3);
strcpy( sp1, "abcdefghi" );
printf("sp1 = %s\n", sp1);
printf("sp3 = %s\n", sp3);
return 0;
}
sp1 = 0x670188 sp2 = 0x670198 sp1 = 0x670188 sp2 = 0x670198 sp3 = 0x670188 sp1 = abcdefghi sp3 = abcdefghi
Task 10
#include <stdio.h>
int main(void){
printf("main = %p\n", main);
return 0;
}
local_str = 0x22cc40