Question

PLease explain output of these two programs:

1.

#include <stdio.h>

typedef struct {
char *name;
int x, y;
int h, w;
} box;

typedef struct {
unsigned int baud : 5;
unsigned int div2 : 1;
unsigned int use_external_clock : 1;
} flags;

int main(int argc, char** argv){

printf("The size of box is %d bytes\n", sizeof(box));
printf("The size of flags is %d bytes\n", sizeof(flags));
return 0;
}

2.

#include <stdio.h>
#include <string.h>

/* define simple structure */
struct {
unsigned int widthValidated;
unsigned int heightValidated;
} status1;

/* define a structure with bit fields */
struct {
unsigned int widthValidated : 1;
unsigned int heightValidated : 1;
} status2;

int main( ) {

printf( "Memory size occupied by status1 : %d\n", sizeof(status1));
printf( "Memory size occupied by status2 : %d\n", sizeof(status2));

return 0;
}

Answer 1

Answer:

Note: in both the C programms while printing the size in main function you wrote data specified as integer but the size of structure will return the unsigned long so we need to change it %lu to get the output or else it will through output.

Here is the Modification of codes with explanation as comments and output

1.

//including header for standard input and output

#include <stdio.h>

typedef struct {

//data members in structre

char *name;

int x, y;

int h, w;

} box;

typedef struct {

//another structure with bit field assigned values

unsigned int baud : 5;

unsigned int div2 : 1;

unsigned int use_external_clock : 1;

} flags;

//main

int main(int argc, char** argv){

//printing the size of structure called box

printf("The size of box is %lu bytes\n", sizeof(box));

//printing the size of structure called flags

printf("The size of flags is %lu bytes\n", sizeof(flags));

return 0;

}

Editor:

1 2 3 4 5 6 8 10 main.c //including header for standard input and output #include <stdio.h> typedef struct { //data members in structre char *name; int x, y: 7 int h, w; } box; 9 typedef struct { 11 1/another structure with bit field assigned values unsigned int baud : 5; 13 unsigned int div2 : 1; unsigned int use_external_clock : 1; } flags; 16 //main 17 int main(int argc, char** argv) { //printing the size of structure called box printf("The size of box is flu bytes\n", sizeof(box)); 20 1/printing the size of structure called flags printf("The size of flags is flu bytes\n", sizeof (flags)); 22 return 0; 23 12 14 15 18 19 21 }

output:

> ./main The size of box is 24 bytes The size of flags is 4 bytes

2.

//including necessary headers

#include <stdio.h>

#include <string.h>

/* define simple structure */

struct {

//data inside the structure

unsigned int widthValidated;

unsigned int heightValidated;

} status1;

/* define a structure with bit fields */

struct {

unsigned int widthValidated : 1;

unsigned int heightValidated : 1;

} status2;

//main

int main( ) {

//print the size of structure without bit fields

printf( "Memory size occupied by status1 : %lu\n", sizeof(status1));

//print the size of struct with bit fields

printf( "Memory size occupied by status2 : %lu\n", sizeof(status2));

return 0;

}

Editor:

1 2 3 4 5 9 10 main.c //including necessary headers #include <stdio.h> #include <string.h> /* define simple structure */ struct { 6 /data inside the structure 7 unsigned int widthvalidated; 8 unsigned int heightValidated; } status1; /* define a structure with bit fields */ 11 struct { 12 unsigned int widthvalidated : 1; 13 unsigned int heightValidated : 1; } status2; //main 16 int main() { 17 //print the size of structure without bit fields printf( "Memory size occupied by statusi : %lu\n", sizeof(status1)); 19 //print the size of struct with bit fields 20 printf( "Memory size occupied by status2 : %lu\n", sizeof(status2)); return; 22 ) 14 15 18 21

output:

./main Memory size occupied by statusi : 8 Memory size occupied by status2 : 4 >

Hope this helps you! If you still have any doubts or queries please feel free to comment in the comment section.

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