Structure pointer returning the start byte of member of structure [duplicate]

-3

This question already has an answer here:

Crash or “segmentation fault” when data is copied/scanned/read to an uninitialized pointer

4 answers

Structure pointer returning the start byte of member of structure
.I wondered how it works. PLease some one help me to get know about this.

 #include <stdio.h>



 typedef struct node {

  char mem;

  double mem2;

  char mem3;

  int mem4;

  char mem5;

  char mem6;

 }NODE;

 int main()

 {

     NODE * m;

     printf("%u",&m->mem3);

     return 0;

 }

Output is 16

edited Nov 20 '18 at 10:37

asked Nov 20 '18 at 9:53

AADHI A.R

155

marked as duplicate by Some programmer dude c
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Nov 20 '18 at 9:57

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

2

You are not allocating memory for NODE *m. You are invoking undefined behavior.

– Micha Wiedenmann
Nov 20 '18 at 9:55

Can you elaborate on your problem?

– Sourav Ghosh
Nov 20 '18 at 9:56

More or less the exact same question as this one. Please tell the rest of your class to not post duplicates.

– Some programmer dude
Nov 20 '18 at 9:58

Also, change the print to printf("%c", m->mem3);. Note how you don't need the &, you're already dereferencing with the -> operator.

– Blaze
Nov 20 '18 at 9:59

Its is returning the starting byte of structure member here.(i.e) mem-0, mem2-8 , mem3 -16, mem4 -20 ,mem5-24 , mem6 - 25. How it returning the starting byte number. @ Micha Wiedenmann @ Sourav Ghosh @Blaze

– AADHI A.R
Nov 20 '18 at 10:03

|
show 20 more comments

-3

This question already has an answer here:

Crash or “segmentation fault” when data is copied/scanned/read to an uninitialized pointer

4 answers

Structure pointer returning the start byte of member of structure
.I wondered how it works. PLease some one help me to get know about this.

 #include <stdio.h>



 typedef struct node {

  char mem;

  double mem2;

  char mem3;

  int mem4;

  char mem5;

  char mem6;

 }NODE;

 int main()

 {

     NODE * m;

     printf("%u",&m->mem3);

     return 0;

 }

Output is 16

edited Nov 20 '18 at 10:37

asked Nov 20 '18 at 9:53

AADHI A.R

155

marked as duplicate by Some programmer dude c
Users with the c badge can single-handedly close c questions as duplicates and reopen them as needed.

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Nov 20 '18 at 9:57

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

2

You are not allocating memory for NODE *m. You are invoking undefined behavior.

– Micha Wiedenmann
Nov 20 '18 at 9:55

Can you elaborate on your problem?

– Sourav Ghosh
Nov 20 '18 at 9:56

More or less the exact same question as this one. Please tell the rest of your class to not post duplicates.

– Some programmer dude
Nov 20 '18 at 9:58

Also, change the print to printf("%c", m->mem3);. Note how you don't need the &, you're already dereferencing with the -> operator.

– Blaze
Nov 20 '18 at 9:59

Its is returning the starting byte of structure member here.(i.e) mem-0, mem2-8 , mem3 -16, mem4 -20 ,mem5-24 , mem6 - 25. How it returning the starting byte number. @ Micha Wiedenmann @ Sourav Ghosh @Blaze

– AADHI A.R
Nov 20 '18 at 10:03

|
show 20 more comments

-3

This question already has an answer here:

Crash or “segmentation fault” when data is copied/scanned/read to an uninitialized pointer

4 answers

Structure pointer returning the start byte of member of structure
.I wondered how it works. PLease some one help me to get know about this.

 #include <stdio.h>



 typedef struct node {

  char mem;

  double mem2;

  char mem3;

  int mem4;

  char mem5;

  char mem6;

 }NODE;

 int main()

 {

     NODE * m;

     printf("%u",&m->mem3);

     return 0;

 }

Output is 16

edited Nov 20 '18 at 10:37

asked Nov 20 '18 at 9:53

AADHI A.R

155

This question already has an answer here:

Crash or “segmentation fault” when data is copied/scanned/read to an uninitialized pointer

4 answers

Structure pointer returning the start byte of member of structure
.I wondered how it works. PLease some one help me to get know about this.

 #include <stdio.h>



 typedef struct node {

  char mem;

  double mem2;

  char mem3;

  int mem4;

  char mem5;

  char mem6;

 }NODE;

 int main()

 {

     NODE * m;

     printf("%u",&m->mem3);

     return 0;

 }

Output is 16

This question already has an answer here:

Crash or “segmentation fault” when data is copied/scanned/read to an uninitialized pointer

4 answers

c memory struct segmentation-fault

edited Nov 20 '18 at 10:37

asked Nov 20 '18 at 9:53

AADHI A.R

155

edited Nov 20 '18 at 10:37

asked Nov 20 '18 at 9:53

AADHI A.R

155

edited Nov 20 '18 at 10:37

asked Nov 20 '18 at 9:53

AADHI A.R

155

asked Nov 20 '18 at 9:53

AADHI A.R

155

asked Nov 20 '18 at 9:53

AADHI A.R

155

marked as duplicate by Some programmer dude c
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Nov 20 '18 at 9:57

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

marked as duplicate by Some programmer dude c
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Nov 20 '18 at 9:57

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

2

You are not allocating memory for NODE *m. You are invoking undefined behavior.

– Micha Wiedenmann
Nov 20 '18 at 9:55

Can you elaborate on your problem?

– Sourav Ghosh
Nov 20 '18 at 9:56

More or less the exact same question as this one. Please tell the rest of your class to not post duplicates.

– Some programmer dude
Nov 20 '18 at 9:58

Also, change the print to printf("%c", m->mem3);. Note how you don't need the &, you're already dereferencing with the -> operator.

– Blaze
Nov 20 '18 at 9:59

Its is returning the starting byte of structure member here.(i.e) mem-0, mem2-8 , mem3 -16, mem4 -20 ,mem5-24 , mem6 - 25. How it returning the starting byte number. @ Micha Wiedenmann @ Sourav Ghosh @Blaze

– AADHI A.R
Nov 20 '18 at 10:03

|
show 20 more comments

2

You are not allocating memory for NODE *m. You are invoking undefined behavior.

– Micha Wiedenmann
Nov 20 '18 at 9:55

Can you elaborate on your problem?

– Sourav Ghosh
Nov 20 '18 at 9:56

More or less the exact same question as this one. Please tell the rest of your class to not post duplicates.

– Some programmer dude
Nov 20 '18 at 9:58

Also, change the print to printf("%c", m->mem3);. Note how you don't need the &, you're already dereferencing with the -> operator.

– Blaze
Nov 20 '18 at 9:59

Its is returning the starting byte of structure member here.(i.e) mem-0, mem2-8 , mem3 -16, mem4 -20 ,mem5-24 , mem6 - 25. How it returning the starting byte number. @ Micha Wiedenmann @ Sourav Ghosh @Blaze

– AADHI A.R
Nov 20 '18 at 10:03

You are not allocating memory for NODE *m. You are invoking undefined behavior.

– Micha Wiedenmann
Nov 20 '18 at 9:55

Can you elaborate on your problem?

– Sourav Ghosh
Nov 20 '18 at 9:56

More or less the exact same question as this one. Please tell the rest of your class to not post duplicates.

– Some programmer dude
Nov 20 '18 at 9:58

Also, change the print to printf("%c", m->mem3);. Note how you don't need the &, you're already dereferencing with the -> operator.

– Blaze
Nov 20 '18 at 9:59

Its is returning the starting byte of structure member here.(i.e) mem-0, mem2-8 , mem3 -16, mem4 -20 ,mem5-24 , mem6 - 25. How it returning the starting byte number. @ Micha Wiedenmann @ Sourav Ghosh @Blaze

– AADHI A.R
Nov 20 '18 at 10:03

|
show 20 more comments

1 Answer
1

active

oldest

votes

The program actually should crash because pointer m is not pointing valid memory location. Below code can give the result.

NODE M;

NODE *ptr = &m;

Printf(“%x”, &ptr->mem3);

%x will give hexadecimal address value.

answered Nov 20 '18 at 10:02

anand

1375

It is not crashing you can compile and check also.

– AADHI A.R
Nov 20 '18 at 10:08

For pointers you should not use %x but %p format specifier.

– Gerhardh
Nov 20 '18 at 11:18

add a comment |

1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

The program actually should crash because pointer m is not pointing valid memory location. Below code can give the result.

NODE M;

NODE *ptr = &m;

Printf(“%x”, &ptr->mem3);

%x will give hexadecimal address value.

answered Nov 20 '18 at 10:02

anand

1375

It is not crashing you can compile and check also.

– AADHI A.R
Nov 20 '18 at 10:08

For pointers you should not use %x but %p format specifier.

– Gerhardh
Nov 20 '18 at 11:18

add a comment |

The program actually should crash because pointer m is not pointing valid memory location. Below code can give the result.

NODE M;

NODE *ptr = &m;

Printf(“%x”, &ptr->mem3);

%x will give hexadecimal address value.

answered Nov 20 '18 at 10:02

anand

1375

It is not crashing you can compile and check also.

– AADHI A.R
Nov 20 '18 at 10:08

For pointers you should not use %x but %p format specifier.

– Gerhardh
Nov 20 '18 at 11:18

add a comment |

The program actually should crash because pointer m is not pointing valid memory location. Below code can give the result.

NODE M;

NODE *ptr = &m;

Printf(“%x”, &ptr->mem3);

%x will give hexadecimal address value.

answered Nov 20 '18 at 10:02

anand

1375

The program actually should crash because pointer m is not pointing valid memory location. Below code can give the result.

NODE M;

NODE *ptr = &m;

Printf(“%x”, &ptr->mem3);

%x will give hexadecimal address value.

answered Nov 20 '18 at 10:02

anand

1375

answered Nov 20 '18 at 10:02

anand

1375

answered Nov 20 '18 at 10:02

anand

1375

answered Nov 20 '18 at 10:02

anand

1375

It is not crashing you can compile and check also.

– AADHI A.R
Nov 20 '18 at 10:08

For pointers you should not use %x but %p format specifier.

– Gerhardh
Nov 20 '18 at 11:18

add a comment |

It is not crashing you can compile and check also.

– AADHI A.R
Nov 20 '18 at 10:08

For pointers you should not use %x but %p format specifier.

– Gerhardh
Nov 20 '18 at 11:18

It is not crashing you can compile and check also.

– AADHI A.R
Nov 20 '18 at 10:08

For pointers you should not use %x but %p format specifier.

– Gerhardh
Nov 20 '18 at 11:18

add a comment |

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