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#include <stdio.h>
int main()
{
int a[][3] = {1, 2, 3, 4, 5, 6};
int (*ptr)[3] = a;
printf("%d %d ", (*ptr)[1], (*ptr)[2]);
++ptr;
printf("%d %d\n", (*ptr)[1], (*ptr)[2]);
return 0;
}


(a) 2 3 5 6 (b) 2 3 4 5
(c) 4 5 0 0 (d) none of the above

asked in Programming by (33 points)   | 435 views
ans  A?
Explanation?

int (*ptr)[3]  // ptr is a poinetr it stores 3 integer values.

int (*ptr)[3]=a; // it stores address of a.

(*ptr)[1] array of first element and (*ptr[2]) array of 2nd element.those are 2,3

(++ptr) it is  increased .it access 2nd dimensional array 

again (*ptr[1]) and (*ptr[2]) elements are 5,6

http://stackoverflow.com/questions/13910749/difference-between-ptr10-and-ptr10

int a[][3] = {1, 2, 3, 4, 5, 6};
int (*ptr)[3] = a;

Can u explain the structure for this 2 lines

2)ptr is a pointer to an array of storing 3 integer values.

ptr contains address of a.suppose address of a=1000 then 

 

 

it is giving result as 2,3,5,6 @vishal
@santhosh convert it as answer .  Perhaps Many of your comments should have to be converted to answers :)
Does the above structure for the 2D array is correct? . Because i was unable to visualise the 2D array structure with rows not mentioned.
two 2-d arrays a[0] and a[1]

in which a[0]---a[0][0] ,a[0][1],a[0[2] elements are 1,2,3

same as a[1]--a[1][0],a[1][1],a[1][2] elements are 4,5,6

1 Answer

+2 votes
Best answer
int *ptr[10];

This is an array of 10 int* pointers

int (*ptr)[10];

This is a pointer to an array of 10 int

  *(*a+1)   (*a)[1]  are two diffferent representation of a[0][1]

 

$int (*ptr)[3] $ // is nothing but  ptr[][]

$int (*ptr)[3]=a;$ // it stores address of a .

$(*ptr)[1]  $first element  // nothing but a[0][1]  which print 2
$(*ptr[2]) $ 2nd element. // // nothing but a[0][2] which print 3

$(++ptr)$ it is  increased .it access 2nd dimensional array 

$(*ptr)[1] $ first element  // nothing but a[1][1]  which print 5
$(*ptr[2])$  2nd element. // // nothing but a[1][2] which print 6

Output is $2,3,5,6$

http://stackoverflow.com/questions/13910749/difference-between-ptr10-and-ptr10

 

answered by Veteran (11k points)  
edited by


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