Programming problems
- 1. What would be the output of the following program? /* sample.c */ main ( int argc, char **argv ) { argc = argc - (argc -1); printf ("%s", argv[argc - 1]); } Discuss
Correct Answer: C: \SAMPLEEXE
- 2. If the following program (myprog) is run from the command line as myprog 1 2 3 what would be the output? main(int argc, char *argv[]) { int i, j = 0; for (i = 0; i < argc ; i++) j = j + atoi ( argv[i]); printf ("%d", j); }
Options- A. 123
- B. 6
- C. Error
- D. "123" Discuss
Correct Answer: 6
Explanation:
When atoi() tries to convert argv[0] to a number it cannot do so (argv[0] being a file name) and hence returns a zero.
- 3. What would be the output of the following program ? main() { unsigned int a = oxffff; ~a; printf ("%x", a); }
Options- A. ffff
- B. 0000
- C. 00ff
- D. None of the above Discuss
Correct Answer: ffff
- 4. Answer the following Program #define CHARSIZE 8 #define MASK(y) (1 << y % CHARSIZE) #define BITSLOT (y) (y / CHARSIZE) #define SET(x,y) ( x[BITSLOT(y)] = MASK(y) ) #define TEST(x,y) ( x[BITSLOT(y)] & MASK(y) ) #define NUMSLOTS(n) ((n + CHARSIZE - 1) / CHARSIZE) Give the above macros how would you 1. declare an array arr of 50 bits 2. put the 20th bit on 3. test whether the 40th bit is on or off Discuss
Correct Answer: 1 char arr[NUMSLOTS(50)]; 2 SET (arr, 20); 3 if (TEST (arr, 40))
- 5. In the following code can we declare a new typedef name emp even though struct employee has not been completely defined while using typedef? < Yes / No> typedef struct employee *ptr; struct employee { char name[20]; int age; ptr next; }; Discuss
Correct Answer: Yes
- 6. Improve the following code using typedef. struct node { int data1; float data2; struct node *left; struct node *right; }; struct node *ptr; ptr = (struct node *) malloc (sizeof (struct node) ); Discuss
Correct Answer: typedef struct node * treeptr typedef struct node { int data1; float data2; treeptr *left; treeptr *right; }treenode; treeptr ptr; ptr = ( treeptr ) malloc ( sizeof ( treenode ) );
- 7. How would you dynamically allocate a 2-D array of integers? Discuss
Correct Answer: #include "alloch" #define MAXROW 3 #define MAXcol 4 main() { int *p, i, J; p = (int *) malloc (MAXROW * MAXCOL * sizeof (int)); for ( i=0; i < MaxROW ; i++) { for (j=0; j < MAXCOL ; j++) { p [ i * MAXCOL + j] = i; printf ( "%d", p [i * MAXCOL + j] ); } printf ("\n"); } }
- 8. How would you free the memory allocated by the following program? #include "alloc.h" #define MAXROW 3 #define MAXCOL 4 main() { int **p, i; p = (int **) malloc (MAXROW * sizeof (int *)); for ( i = 0; i < MAXROW ; i++) p[i] = (int *) malloc (MAXCOL * sizeof (int )); } Discuss
Correct Answer: for ( i=0; i < MAXROW ; i++) free (p[i]); free (p);
- 9. Can I increase the size of a dynamically allocated array? < Yes / No> if yes, how? Discuss
Correct Answer: Yes, using the realloc() function as shown below: main() { int *p; p = ( int *) malloc (20) ; t = p; t = (int *) realloc ( p, 40); if ( t == NULL ) Printf (" Cannot reallocate, leaves previous allocated region unchanged "); else { if ( p ==t ) ; / * the array expanded at the same region */ else { free ( p ); / * deallocate the original array */ p = t; /* set p to newly allocated region */ } } }
- 10. What is the difference between malloc() and calloc() functions? Discuss
Correct Answer: As against malloc(), calloc() needs two arguments, the number of elements to be allocated and the size of each element For example, p = (int *) calloc (10, sizeof (int)); would allocate space for a 10- integer array Additionally, calloc() would also set each of this element with a value 0 Thus the above call to calloc() is equivalent to: p = (int *) malloc (10 * sizeof (int)); memset (p, 0, 10 * sizeof( int ));
More in Technical Questions:
Programming
Copyright ©CuriousTab. All rights reserved.