Here is a listing of C programming questions on “Pointers to Pointers” along with answers, explanations and/or solutions:
1. What substitution should be made to //-Ref such that ptr1 points to variable c in the following C code?
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#include -
int main()
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{ -
int a = 1, b = 2, c = 3;
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int *ptr1 = &a;
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int **sptr = &ptr1;
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//-Ref -
}
a) *sptr = &c;
b) **sptr = &c;
c) *ptr1 = &c;
d) none of the mentioned
Answer: a
Clarification: None.
2. Which of the following declaration will result in run-time error?
a) int **c = &c;
b) int **c = &*c;
c) int **c = **c;
d) none of the mentioned
Answer: d
Clarification: None.
3. Comment on the output of the following C code.
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#include -
int main()
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{ -
int a = 10;
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int **c -= &&a;
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}
a) You cannot apply any arithmetic operand to a pointer
b) We don’t have address of an address operator
c) We have address of an address operator
d) None of the mentioned
Answer: b
Clarification: None.
4. What will be the output of the following C code?
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#include -
void main()
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{ -
int k = 5;
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int *p = &k;
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int **m = &p;
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printf("%d%d%dn", k, *p, **m);
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}
a) 5 5 5
b) 5 5 junk value
c) 5 junk junk
d) Compile time error
Answer: a
Clarification: None.
5. What will be the output of the following C code?
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#include -
void main()
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{ -
int k = 5;
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int *p = &k;
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int **m = &p;
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printf("%d%d%dn", k, *p, **p);
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}
a) 5 5 5
b) 5 5 junk value
c) 5 junk junk
d) Compile time error
Answer: d
Clarification: None.
6. What will be the output of the following C code?
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#include -
void main()
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{ -
int k = 5;
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int *p = &k;
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int **m = &p;
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**m = 6;
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printf("%dn", k);
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}
a) 5
b) Run time error
c) 6
d) Junk
Answer: c
Clarification: None.
7. What will be the output of the following C code?
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#include -
void main()
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{ -
int a[3] = {1, 2, 3};
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int *p = a;
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int *r = &p;
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printf("%d", (**r));
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}
a) 1
b) Compile time error
c) Address of a
d) Junk value
Answer: b
Clarification: None.