C Programming and Problem Solving Questions and Answers 161 to 170

C Programming and Problem Solving

Questions 161 to 170



161.
In ‘C’ which of the following can be used to create the constants for float values
i) Enumerations             ii) const                                                iii) # define
(a)  i & ii                 (b)  ii only                (c)  ii & iii                 (d)  i & iii                 (e)  iii only.
162.
Choose the correct output for the following given program.
       # include <stdio.h>
       void fun(int a, int b, …)
       {
              int i=0, *p = &b;
              for( printf(“    ”);  i<a;  i++)
                     printf(“%d, ”, ++(*p++));
       }
       void main()
       {
              fun(1, 0);
              fun(3,1,2,3);
       }
(a)  Syntax error      (b)  1,     2, 3, 4       (c)  run time error     (d)  0,    1,2,3        (e)  1,    1,2,3.
163.
For the following input function scanf(“%d%*d%d”, &x, &y);    if the values entered are 900  456  786.  Then what will be the values of integer variables x, y.
(a)  900   456                                         (b)  456   786                                         (c)  900                  
(d)  900   786                                         (e)  Abnormal program termination.
164.
What is the output of the following program?
# include <stdio.h>
void main()
{
       int a=5, *pa=&a, b=0, *pb=&b, **ppa=&pa;
       pb=pa;
       a += *pb += **ppa;
       printf(“ %d, ”  “%d, ”  “%d”, *pa, b, **ppa);
}

(a)  20, 0, 20           (b)  20, 20, 20          (c)  Syntax Error      (d)  0, 20, 0             (e)  0, 20, 20.
165.
What is the output of the following program
       # include <stdio.h>
       struct temp {
                     int j, i;
                     }a;
       void fun(struct temp *p)
       {
              printf(“%d, “, *p);         p++;     printf(“%d”, *p);
       }
       void main()
       {
              struct temp *z = &a;
              z->i = 1,  z->j = 10;
              fun(z);
       }
(a)  10, 10               (b)  10, 1                 (c)  1, 10                 (d)  0, 10                 (e)  10, 0.
166.
What would be the values assigned to a, b, c if the following statement is extended with input data item 123456 scanf(“%d %d %d”, &a, &b, &c );
(a)  a=12, b=34, c=56                                                          (b)  a=123456 and nothing is assigned to b, c             
(c)  a=1, b=3, c=5                                  (d)  a, b are not assigned any thing but c=123456         
(e)  a=123456, b=0, c=0.
167.
If the following loop is implemented then ..        
       {
              static int  x;
              do {
                     --x;
                     printf( “%d”, x++);
              }while( x >= 0);
       }
(a)   The program will not enter in the loop                            
(b)  There will be a compilation error reported                       
(c)  The loop will run infinitely                 
(d)  A run time error will be reported
(e)  It prints 0 once and terminates the do – while loop successfully.
168.
The expression (( fileptr = fopen(“somefile”, “w”)) == NULL ) would be true if
(a)  The file somefile is read only          
(b)  May be the fileptr is not declared as a FILE pointer         
(c)  The file somefile does not exist while fopen function is being executed         
(d)  The file somefile could  not be created for writing           
(e)  Both (b) and (c) above.
169.
The given statement  FILE *fptr;
(a)  Defines a pointer to the pre-defined structure type FILE
(b)  Defines a pointer to the user-defined structure type FILE
(c)  Defines a pointer to the pre-defined data type FILE DESCRIPTOR
(d)  Creates a file with the name fptr
(e)  Creates a file pointed by fptr.
170.
The getchar() library function
(a)   Returns a character when any key is pressed
(b)   Returns multiple characters when the keys are pressed
(c)   Returns multiple characters when the keys are pressed followed by enter key
(d)   Both (b) and (c) above
(e)   Returns a single character when the keys are pressed followed by enter key.



Answers


161.
Answer : (c)
Reason:  const, # define can be used to create any constant of any primitive data type, but Enumerations are only used to create the integer symbolic constants
162.
Answer : (b)
Reason:  It is same as variable length arguments list. See any book for variable length arguments list. Be keen at printf (“%d, ”, ++(*p++));
163.
Answer : (d)
Reason:  Because this form %*format_specifier suppress the input and do not store it in any variable, and hence 456 is skipped.
164.
Answer : (a)  
Reason:  Because of pointers (*pa=&a, *pb=&b) and pointer to pointer (**ppa=&pa) and the short form operators (+= )
pb=pa;
       a += *pb += **ppa;
       printf(“ %d, ” “%d, ” “%d”, *pa, b, **ppa);
165.
Answer : (e)
Reason:  Because of the set of statements struct temp *z = &a; z->i = 1, z->j = 10; pointer is pointing to first field and hence in response to printf(“%d, “, *p); it printed the value of j (see the order int j, i; in structure definition temp). And once the pointer is incremented it crosses the current structure variable (a) and pointing to some other location. So in response to printf (“%d”, *p); the output was 0.
166.
Answer : (b)
Reason:  Because there is no width specification on input, hence a single input value 123456 is assigned to first variable i.e., a, and b, c are not assigned with any value.
167.
Answer : (c)
Reason:  The loop will run infinitely, because the statement static int x; causes the value to x be set a 0, and in do – while (x >= 0), loop we are decrementing (--x) and after again incrementing the value of x by one in printf (“%d”, x++); so the value of x remains 0 for each iteration of loop. And hence infinite loop
168.
Answer : (d)
Reason:  Because according to the definition of fopen () it returns the pointer to the FILE pointer in success and returns NULL in failure (means could not open the file for writing). Hence it is the most suitable answer when compared with all the other options given.
169.
Answer : (a)
Reason:  Because FILE is a pre-defined (system defined) structure of type FILE. Hence the given statement FILE *fptr; only creates a pointer to the pre-defined structure type FILE, also FILE it neither a user-defined structure type (FILE) nor a pre-defined data type (FILE DESCRIPTOR) by definition of itself. Also no file is created without using fopen ().
170.
Answer : (e)
Reason:  Because the getchar () function reads the input characters until enter key is pressed, and returns a single character only ( the first character in the input )


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