1. What is the output of this C code?
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#include <stdio.h> -
int main()
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{ -
char *p = NULL;
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char *q = 0;
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if (p)
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printf(" p ");
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else -
printf("nullp");
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if (q)
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printf("qn");
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else -
printf(" nullqn");
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}
a) nullp nullq
b) Depends on the compiler
c) x nullq where x can be p or nullp depending on the value of NULL
d) p q
Answer
Answer: a [Reason:] None.
2. What is the output of this C code?
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#include <stdio.h> -
int main()
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{ -
int i = 10;
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void *p = &i;
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printf("%dn", (int)*p);
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return 0;
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}
a) Compile time error
b) Segmentation fault/runtime crash
c) 10
d) Undefined behaviour
Answer
Answer: a [Reason:] None.
3. What is the output of this C code?
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#include <stdio.h> -
int main()
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{ -
int i = 10;
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void *p = &i;
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printf("%fn", *(float*)p);
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return 0;
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}
a) Compile time error
b) Undefined behaviour
c) 10
d) 0.000000
Answer
Answer: d [Reason:] None.
4. What is the output of this C code?
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#include <stdio.h> -
int *f();
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int main()
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{ -
int *p = f();
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printf("%dn", *p);
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} -
int *f()
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{ -
int *j = (int*)malloc(sizeof(int));
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*j = 10;
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return j;
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}
a) 10
b) Compile time error
c) Segmentation fault/runtime crash since pointer to local variable is returned
d) Undefined behaviour
Answer
Answer: a [Reason:] None.
5. What is the output of this C code?
-
#include <stdio.h> -
int *f();
-
int main()
-
{ -
int *p = f();
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printf("%dn", *p);
-
} -
int *f()
-
{ -
int j = 10;
-
return &j;
-
}
a) 10
b) Compile time error
c) Segmentation fault/runtime crash
d) Undefined behaviour
Answer
Answer: a [Reason:] We are returning address of a local variable which should not be done. In this specific instance, we are able to see the value of 10, which may not be the case if we call other functions before calling printf() in main().
6. Comment on the following pointer declaration?
int *ptr, p;
a) ptr is a pointer to integer, p is not
b) ptr and p, both are pointers to integer
c) ptr is a pointer to integer, p may or may not be
d) ptr and p both are not pointers to integer
Answer
Answer: a [Reason:] None.
7. What is the output of this C code?
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#include <stdio.h> -
int main()
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{ -
int *ptr, a = 10;
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ptr = &a;
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*ptr += 1;
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printf("%d,%d/n", *ptr, a);
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}
a) 10,10
b) 10,11
c) 11,10
d) 11,11
Answer
Answer: d [Reason:] None.
8. Comment on the following?
const int *ptr;
a) You cannot change the value pointed by ptr
b) You cannot change the pointer ptr itself
c) You May or maynot change the value pointed by ptr
d) You can change the pointer as well as the value pointed by it
Answer
Answer: a [Reason:] None.
