C questions in placement tests and university exams are rarely about syntax alone. Most of what you will find here is output prediction, pointer arithmetic, arrays and strings, structures and unions, storage classes, recursion, and file handling. The explanations walk through memory behaviour step by step, which is usually where the confusion sits rather than in the code itself.
How many times will the following loop execute? int arr[5]; for(int i=0; i<5; i++) arr[i]=0;
Answer: B
Loop runs from i=0 to i=4, executing 5 times total. All array elements are initialized to 0.
Q.22Easy
In C, when you declare an array like int arr[10], what does the array name 'arr' represent?
Answer: A
Array names decay to pointers to their first element in most contexts. 'arr' is equivalent to &arr[0] and cannot be reassigned.
Q.23Easy
What is the size of the string 'Hello' when stored in a character array with null terminator?
Answer: B
'Hello' has 5 characters plus 1 null terminator (\0), making total 6 bytes.
Q.24Easy
Which of the following correctly initializes a 2D array of integers?
Answer: A
Option A is valid - 2D arrays can be initialized with all elements in a single brace. Options B and C are invalid as at least one dimension must be specified.
Q.25Easy
In the declaration char *str[5], what does the array represent?
Answer: A
The syntax char *str[5] declares an array of 5 pointers, each pointing to a character (or string). The brackets bind tighter than asterisk.
Q.26Easy
How many elements can be stored in a 2D array declared as int matrix[4][5]?
Answer: D
A 2D array with dimensions [4][5] contains 4 × 5 = 20 elements total.
Q.27Easy
What is the correct way to declare and initialize a string in C?
Answer: B
Option B shows two valid ways: pointer to string literal or character array. Option A is wrong (single char), C is wrong (no String type in C).
Q.28Easy
What is the output of: int arr[] = {10, 20, 30}; printf("%d", *(arr+1));?
Answer: B
arr+1 points to second element (arr[1]). Dereferencing gives value 20.
Q.29Easy
What will be the size in bytes of int arr[5] on a 32-bit system?
Answer: C
On 32-bit systems, int is typically 4 bytes. 5 elements × 4 bytes = 20 bytes total.
Q.30Easy
Consider the following code:
char str[] = "HELLO"; int len = 0; while(str[len] != '\0') { len++; } printf("%d", len);
What will be the output?
Answer: A
The string "HELLO" has 5 characters. The while loop counts characters until it encounters the null terminator '\0'. The output will be 5. The null terminator is not counted in the length.
