What is the correct way to declare a 1D array of 10 integers in C?
Answer: A
In C, arrays are declared with the syntax: datatype arrayname[size]. Option A follows the correct syntax.
Q.2Easy
What will be the output of strlen("Hello") in C?
Answer: B
strlen() returns the length of the string excluding the null terminator '\0'. "Hello" has 5 characters.
Q.3Easy
Which of the following is NOT a valid string initialization?
Answer: C
Array names are constant pointers and cannot be reassigned. Direct assignment to char array after declaration is invalid.
Q.4Easy
What does the following code do? strcpy(dest, src);
Answer: B
strcpy() copies the contents of the source string to the destination string.
Q.5Easy
Consider a 2D array declared as: int matrix[3][4]. How many elements does it have?
Answer: D
A 2D array with dimensions 3x4 has 3*4 = 12 total elements.
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Q.6Medium
What will be the output of the following code?
char str[] = "Code";
printf("%c", str[2]);
Answer: C
String "Code" has indices: C(0), o(1), d(2), e(3). str[2] refers to 'd'.
Q.7Medium
What is the difference between char str[] = "Test" and char *str = "Test"?
Answer: B
char[] creates a modifiable array with its own storage. char* points to read-only string literal in memory.
Q.8Medium
Which function is used to reverse a string in C library?
Answer: C
There is no standard library function for string reversal. strrev() is non-standard (available in some compilers). Manual reversal or custom functions are needed.
Q.9Medium
What is the output of the following code?
int arr[] = {10, 20, 30};
printf("%d", sizeof(arr)/sizeof(arr[0]));
Answer: C
sizeof(arr) gives total bytes of array. sizeof(arr[0]) gives bytes of one element. Division gives number of elements: 3.
Q.10Medium
What will be printed by: printf("%s", "Hello\0World");?
Answer: B
\0 is the null terminator which marks the end of a string. %s stops printing at the first null character.
Q.11Medium
Consider: int *ptr = arr; where arr is an array. What does ptr[2] represent?
Answer: B
ptr[2] is equivalent to *(ptr+2), which points to the third element (index 2) of the array.
Q.12Medium
What will the following code output?
char str[20];
strcpy(str, "Competitive");
strcat(str, " Exam");
printf("%s", str);
Answer: C
strcpy copies "Competitive" to str. strcat appends " Exam" to it, resulting in "Competitive Exam".
Q.13Medium
What is the time complexity of searching for an element in an unsorted array of size n?
Answer: C
Linear search on unsorted array requires checking each element in worst case, giving O(n) time complexity.
Q.14Medium
What will be the output of this code?
int arr[5];
for(int i=0; i<5; i++) arr[i] = i*i;
printf("%d %d %d", arr[1], arr[2], arr[4]);
