C Aptitude Questions with Answers Part 19

96)

void main() {
  static int i=5; 
  if(--i){ 
    main(); 
    printf("%d ",i); 
  } 
} 

Answer:
0 0 0 0
Explanation:
  The variable "I" is declared as static, hence memory for I will be allocated for only once, as it encounters the statement. The function main() will be called recursively unless I becomes equal to 0, and since main() is recursively called, so the value of static I ie., 0 will be printed every time the control is returned.

97)

void main() {
  int k=ret(sizeof(float)); 
  printf("\n here value is %d",++k); 
} 
int ret(int ret) {
  ret += 2.5; 
  return(ret); 
} 

Answer:
Here value is 7
Explanation:
  The int ret(int ret), ie., the function name and the argument name can be the same. Firstly, the function ret() is called in which the sizeof(float) ie., 4 is passed,  after the first expression the value in ret will be 6, as ret is integer hence the value stored in ret will have implicit type conversion from float to int. The ret is returned in
main() it is printed after and preincrement.

98)

void main() {
  char a[]="12345\0"; 
  int i=strlen(a); 
  printf("here in 3 %d\n",++i); 
} 

Answer:
here in 3 6
Explanation:
  The char array 'a' will hold the initialized string, whose length will be counted from 0 till the null character. Hence the 'I' will hold the value equal to 5, after the pre-increment in the printf statement, the 6 will be printed.

99)

void main() {
  unsigned giveit=-1; 
  int gotit; 
  printf("%u ",++giveit); 
  printf("%u \n",gotit=--giveit); 
} 

Answer:
0 65535


100)

void main() {
  int i; 
  char a[]="\0"; 
  if(printf("%s\n",a)) 
    printf("Ok here \n"); 
  else 
    printf("Forget it\n"); 
} 

Answer:
Ok here
Explanation:
Printf will return how many characters does it print. Hence printing a null character returns 1 which makes the if statement true, thus "Ok here" is printed.

101)

void main() {
  void *v; 
  int integer=2; 
  int *i=&integer; 
  v=i; 
  printf("%d",(int*)*v); 
} 

Answer:

Compiler Error. We cannot apply indirection on type void*.

Explanation:

Void pointer is a generic pointer type. No pointer arithmetic can be done on it. Void pointers are normally used for,  

1. Passing generic pointers to functions and returning such pointers. 
2. As a intermediate pointer type. 
3. Used when the exact pointer type will be known at a later point of time.