C Practice Test 1

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Suppose that in a C program snippet, followings statements are used. i) sizeof(int); ii) sizeof(int*); iii) sizeof(int**); Assuming size of pointer is 4 bytes and size of int is also 4 bytes, pick the most correct answer from the given options.

• Suppose that in a C program snippet, followings statements are used.
• i), ii) and iii) would compile successfully and size of each would be same i.e. 4
• i), ii) and iii) would compile successfully but the size of each would be different and would be decided at run time.
• ii) and iii) would result in compile error but i) would compile and result in size as 4.

Assume int is 4 bytes, char is 1 byte and float is 4 bytes. Also, assume that pointer size is 4 bytes (i.e. typical case) char *pChar; int *pInt; float *pFloat; sizeof(pChar); sizeof(pInt); sizeof(pFloat); What’s the size returned for each of sizeof() operator?

• 4 4 4
• 1 4 4
• 1 4 8
• None of the above

#include "stdlib.h" int main() { int *pInt; int **ppInt1; int **ppInt2; pInt = (int*)malloc(sizeof(int)); ppInt1 = (int**)malloc(10*sizeof(int*)); ppInt2 = (int**)malloc(10*sizeof(int*)); free(pInt); free(ppInt1); free(*ppInt2); return 0; } Choose the correct statement w.r.t. above C program.

• malloc() for ppInt1 and ppInt2 isn’t correct. It’ll give compile time error.
• free(*ppInt2) is not correct. It’ll give compile time error.
• free(*ppInt2) is not correct. It’ll give run time error.
• No issue with any of the malloc() and free() i.e. no compile/run time error.

#include "stdio.h" int main() { void *pVoid; pVoid = (void*)0; printf("%lu",sizeof(pVoid)); return 0; } Pick the best statement for the above C program snippet.

• Assigning (void *)0 to pVoid isn’t correct because memory hasn’t been allocated. That’s why no compile error but it'll result in run time error.
• Assigning (void *)0 to pVoid isn’t correct because a hard coded value (here zero i.e. 0) can’t assigned to any pointer. That’s why it'll result in compile error.
• No compile issue and no run time issue. And the size of the void pointer i.e. pVoid would equal to size of int.
• sizeof() operator isn’t defined for a pointer of void type.

Consider the following variable declarations and definitions in C i) int var_9 = 1; ii) int 9_var = 2; iii) int _ = 3; Choose the correct statement w.r.t. above variables.

• Both i) and iii) are valid.
• Only i) is valid.
• Both i) and ii) are valid.
• All are valid.

Let x be an integer which can take a value of 0 or 1. The statement if(x = =0) x = 1; else x = 0; is equivalent to which one of the following?

• x = 1 + x;
• x = 1 - x;
• x = x - 1;
• x = 1 % x;

A program attempts to generate as many permutations as possible of the string, 'abcd' by pushing the characters a, b, c, d in the same order onto a stack, but it may pop off the top character at any time. Which one of the following strings CANNOT be generated using this program?

• abcd
• dcba
• cbad
• cabd