Write a program to reverse a string (using standard functions).<\/strong><\/li>\n<\/ol>\n\n\n\nI take a character array, use two pointers\u2014one at the start, one at the end\u2014and swap characters until they meet. Here’s a short example:<\/p>\n\n\n\n
#include <stdio.h><\/p>\n\n\n\n
#include <string.h><\/p>\n\n\n\n
void reverse(char str[]) {<\/p>\n\n\n\n
int i = 0, j = strlen(str) – 1;<\/p>\n\n\n\n
while(i < j) {<\/p>\n\n\n\n
char temp = str[i];<\/p>\n\n\n\n
str[i] = str[j];<\/p>\n\n\n\n
str[j] = temp;<\/p>\n\n\n\n
i++; j–;<\/p>\n\n\n\n
}<\/p>\n\n\n\n
}<\/p>\n\n\n\n
\n- Implement a function to check if a number is a palindrome.<\/strong><\/li>\n<\/ol>\n\n\n\n
I reverse the number and compare it to the original:<\/p>\n\n\n\n
int isPalindrome(int num) {<\/p>\n\n\n\n
int original = num, reversed = 0;<\/p>\n\n\n\n
while(num != 0) {<\/p>\n\n\n\n
reversed = reversed * 10 + num % 10;<\/p>\n\n\n\n
num \/= 10;<\/p>\n\n\n\n
}<\/p>\n\n\n\n
return original == reversed;<\/p>\n\n\n\n
}<\/p>\n\n\n\n
\n- Write a program to find the factorial of a number using recursion.<\/strong><\/li>\n<\/ol>\n\n\n\n
A base case for n == 0, then return n * fact(n – 1).<\/p>\n\n\n\n
int factorial(int n) {<\/p>\n\n\n\n
if(n == 0) return 1;<\/p>\n\n\n\n
return n * factorial(n – 1);<\/p>\n\n\n\n
}<\/p>\n\n\n\n
\n- Implement a binary search algorithm.<\/strong><\/li>\n<\/ol>\n\n\n\n
Binary search splits the array in half and checks mid:<\/p>\n\n\n\n
int binarySearch(int arr[], int n, int key) {<\/p>\n\n\n\n
int low = 0, high = n – 1;<\/p>\n\n\n\n
while(low <= high) {<\/p>\n\n\n\n
int mid = (low + high) \/ 2;<\/p>\n\n\n\n
if(arr[mid] == key) return mid;<\/p>\n\n\n\n
else if(arr[mid] < key) low = mid + 1;<\/p>\n\n\n\n
else high = mid – 1;<\/p>\n\n\n\n
}<\/p>\n\n\n\n
return -1;<\/p>\n\n\n\n
}<\/p>\n\n\n\n
Note \u2013<\/strong> For C coding questions, always focus on writing clean, error-free code and consider edge cases before finalizing your solution.<\/p>\n\n\n\nAlso Read - Top 50+ OOPs Interview Questions and Answers for 2026<\/a><\/strong><\/pre>\n\n\n\n<\/span>C MCQ Interview Questions<\/span><\/h2>\n\n\n\nHere are some important C MCQ interview questions to quickly test your theoretical and practical knowledge of the C language.<\/p>\n\n\n\n
\n- What is the output of the following code snippet?<\/strong><\/li>\n<\/ol>\n\n\n\n
int a = 5;<\/p>\n\n\n\n
printf(“%d”, a++);<\/p>\n\n\n\n
a) 6
b) 5
c) Undefined
d) Compiler Error<\/p>\n\n\n\n
Answer:<\/strong> b) 5<\/p>\n\n\n\n\n- Which of the following is not a valid variable name in C?<\/strong><\/li>\n<\/ol>\n\n\n\n
a) int number;
b) float rate;
c) int variable_count;
d) int $main;<\/p>\n\n\n\n
Answer:<\/strong> d) int $main;<\/p>\n\n\n\n\n- What does the sizeof operator return?<\/strong><\/li>\n<\/ol>\n\n\n\n
a) The length of a variable name
b) The number of bits used by a variable
c) The memory size in bytes of a data type or variable
d) The value stored in a pointer<\/p>\n\n\n\n
Answer:<\/strong> c) The memory size in bytes of a data type or variable<\/p>\n\n\n\n\n- Which keyword is used to prevent any changes in the variable within a C program?<\/strong><\/li>\n<\/ol>\n\n\n\n
a) final
b) constant
c) const
d) static<\/p>\n\n\n\n
Answer:<\/strong> c) const<\/p>\n\n\n\n\n