C Aptitude Questions with Answers Part 26

1)

main() {
   char str1[] = {‘s’,’o’,’m’,’e’}; 
   char str2[] = {‘s’,’o’,’m’,’e’,’\0’}; 
   while (strcmp(str1,str2))  
      printf(“Strings are not equal\n”); 
} 

Answer:
“Strings are not equal”
“Strings are not equal”
….
Explanation:
If a string constant is initialized explicitly with characters, ‘\0’ is not appended automatically to the string. Since str1 doesn’t have null termination, it treats whatever the values that are in the following positions as part of the string until it randomly reaches a ‘\0’. So str1 and str2 are not the same, hence the result.

2)

main() {
  int i = 3; 
  for (;i++=0;) printf(“%d”,i); 
} 
 

Answer:
Compiler Error: Lvalue required.
Explanation:
As we know that increment operators return rvalues and hence it cannot appear on the left hand side of an assignment operation.

3)

void main() {
   int *mptr, *cptr;
   mptr = (int*)malloc(sizeof(int)); 
   printf(“%d”,*mptr); 
   int *cptr = (int*)calloc(sizeof(int),1); 
   printf(“%d”,*cptr); 
} 

Answer:
garbage-value 0
Explanation:
The memory space allocated by malloc is uninitialized, whereas calloc returns the allocated memory space initialized to zeros.

4)

void main() {
  static int i; 
  while(i<=10) 
    (i>2)?i++:i--; 
    printf(“%d”, i); 
} 

Answer:
32767
Explanation:
Since i is static it is initialized to 0. Inside the while loop the conditional operator evaluates to false, executing i--. This continues till the integer value rotates to positive value (32767). The while condition becomes false and hence, comes out of the while loop, printing the i value.

5)

main() {
    int i=10,j=20; 
    j = i, j?(i,j)?i:j:j; 
    printf("%d %d",i,j); 
} 

Answer:
10 10
Explanation:
  The Ternary operator ( ? : ) is equivalent for if-then-else statement. So the question can be written as:
 

if(i,j) {
   if(i,j) 
         j = i; 
    else 
        j = j;       
} else 
    j = j;