Implement basic arithmetic operations (+, -, *, /).
#include
int main() {
char operator;
double num1, num2;
printf("Enter an operator (+, -, *, /): ");
scanf("%c", &operator);
printf("Enter two operands: ");
scanf("%lf %lf", &num1, &num2);
switch (operator) {
case '+':
printf("%.2lf + %.2lf = %.2lf\n", num1, num2, num1 + num2);
break;
case '-':
printf("%.2lf - %.2lf = %.2lf\n", num1, num2, num1 - num2);
break;
case '*':
printf("%.2lf * %.2lf = %.2lf\n", num1, num2, num1 * num2);
break;
case '/':
if (num2 != 0)
printf("%.2lf / %.2lf = %.2lf\n", num1, num2, num1 / num2);
else
printf("Error! Division by zero.\n");
break;
default:
printf("Invalid operator\n");
break;
}
return 0;
}
Convert temperatures between Celsius and Fahrenheit.
#include
int main() {
double temp, converted_temp;
char unit;
printf("Enter temperature followed by unit (C/F): ");
scanf("%lf %c", &temp, &unit);
if (unit == 'C' || unit == 'c') {
converted_temp = (temp * 9/5) + 32;
printf("%.2lf Celsius = %.2lf Fahrenheit\n", temp, converted_temp);
} else if (unit == 'F' || unit == 'f') {
converted_temp = (temp - 32) * 5/9;
printf("%.2lf Fahrenheit = %.2lf Celsius\n", temp, converted_temp);
} else {
printf("Invalid unit\n");
}
return 0;
}
Calculate and print the average of student grades.
#include
int main() {
int n, i;
float grade, sum = 0.0, average;
printf("Enter the number of students: ");
scanf("%d", &n);
for (i = 1; i <= n; ++i) {
printf("Enter grade for student %d: ", i);
scanf("%f", &grade);
sum += grade;
}
average =
sum / n;
printf("Average grade = %.2f\n", average);
return 0;
}
Determine if a number is even or odd.
#include
int main() {
int num;
printf("Enter an integer: ");
scanf("%d", &num);
if (num % 2 == 0) {
printf("%d is even.\n", num);
} else {
printf("%d is odd.\n", num);
}
return 0;
}
Calculate simple interest given principal, rate, and time.
#include
int main() {
float principal, rate, time, interest;
printf("Enter principal amount: ");
scanf("%f", &principal);
printf("Enter rate of interest: ");
scanf("%f", &rate);
printf("Enter time period in years: ");
scanf("%f", &time);
interest = (principal * rate * time) / 100;
printf("Simple interest = %.2f\n", interest);
return 0;
}
User has to guess a number chosen by the program.
#include
#include
#include
int main() {
int number, guess, attempts = 0;
// Initialize random number generator
srand(time(0));
number = rand() % 100 + 1; // Random number between 1 and 100
printf("Guess the number between 1 and 100:\n");
do {
printf("Enter your guess: ");
scanf("%d", &guess);
attempts++;
if (guess > number) {
printf("Lower number please!\n");
} else if (guess < number) {
printf("Higher number please!\n");
} else {
printf("Congratulations! You guessed the number in %d attempts.\n", attempts);
}
} while (guess != number);
return 0;
}
Print all prime numbers up to a given number.
#include
int isPrime(int num) {
if (num <= 1) return 0;
for (int i = 2; i <= num / 2; i++) {
if (num % i == 0) return 0;
}
return 1;
}
int main() {
int limit;
printf("Enter the limit: ");
scanf("%d", &limit);
printf("Prime numbers up to %d are:\n", limit);
for (int i = 2; i <= limit; i++) {
if (isPrime(i)) {
printf("%d ", i);
}
}
printf("\n");
return 0;
}
Print the Fibonacci series up to a certain number.
#include
int main() {
int limit, t1 = 0, t2 = 1, nextTerm = 0;
printf("Enter the limit: ");
scanf("%d", &limit);
printf("Fibonacci Series: %d, %d, ", t1, t2);
nextTerm = t1 + t2;
while (nextTerm <= limit) {
printf("%d, ", nextTerm);
t1 = t2;
t2 = nextTerm;
nextTerm = t1 + t2;
}
printf("\n");
return 0;
}
Calculate the factorial of a given number.
#include
int main() {
int num, i;
unsigned long long factorial = 1;
printf("Enter an integer: ");
scanf("%d", &num);
if (num < 0) {
printf("Factorial of a negative number doesn't exist.\n");
} else {
for (i = 1; i <= num; ++i) {
factorial *= i;
}
printf("Factorial of %d = %llu\n", num, factorial);
}
return 0;
}
Print the multiplication table of a given number.
#include
int main() {
int num;
printf("Enter a number: ");
scanf("%d", &num);
printf("Multiplication Table of %d:\n", num);
for (int i = 1; i <= 10; ++i) {
printf("%d x %d = %d\n", num, i, num * i);
}
return 0;
}
Functions to calculate the area and perimeter of different shapes.
#include
float areaCircle(float radius) {
return 3.14159 * radius * radius;
}
float perimeterCircle(float radius) {
return 2 * 3.14159 * radius;
}
float areaRectangle(float length, float width) {
return length * width;
}
float perimeterRectangle(float length, float width) {
return 2 * (length + width);
}
int main() {
float radius, length, width;
printf("Enter radius of the circle: ");
scanf("%f", &radius);
printf("Area of Circle: %.2f\n", areaCircle(radius));
printf("Perimeter of Circle: %.2f\n", perimeterCircle(radius));
printf("Enter length and width of the rectangle: ");
scanf("%f %f", &length, &width);
printf("Area of Rectangle: %.2f\n", areaRectangle(length, width));
printf("Perimeter of Rectangle: %.2f\n", perimeterRectangle(length, width));
return 0;
}
Check if a string or number is a palindrome.
#include
#include
#include
int isPalindrome(char str[]) {
int len = strlen(str);
for (int i = 0; i < len / 2; i++) {
if (str[i] != str[len - i - 1]) {
return 0;
}
}
return 1;
}
int main() {
char str[100];
printf("Enter a string: ");
scanf("%s", str);
for (int i = 0; i < strlen(str); i++) {
str[i] = tolower(str[i]);
}
if (isPalindrome(str)) {
printf("%s is a palindrome.\n", str);
} else {
printf("%s is not a palindrome.\n", str);
}
return 0;
}
Find the greatest common divisor and least common multiple.
#include
int gcd(int a, int b) {
if (b == 0)
return a;
return gcd(b, a % b);
}
int lcm(int a, int b) {
return (a * b) / gcd(a, b);
}
int main() {
int num1, num2;
printf("Enter two integers: ");
scanf("%d %d", &num1, &num2);
printf("GCD of %d and %d is %d\n", num1, num2, gcd(num1, num2));
printf("LCM of %d and %d is %d\n", num1, num2, lcm(num1, num2));
return 0;
}
Functions to add, subtract, and multiply matrices.
#include
void addMatrices(int rows, int cols, int a[rows][cols], int b[rows][cols], int result[rows][cols]) {
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
result[i][j] = a[i][j] + b[i][j];
}
}
}
void subtractMatrices(int rows, int cols, int a[rows][cols], int b[rows][cols], int result[rows][cols]) {
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
result[i][j] = a[i][j] - b[i][j];
}
}
}
void multiplyMatrices(int r1, int c1, int a[r1][c1], int r2, int c2, int b[r2][c2], int result[r1][c2]) {
for (int i = 0; i < r1; i++) {
for (int j = 0; j < c2; j++) {
result[i][j] = 0;
for (int k = 0; k < c1; k++) {
result[i][j] += a[i][k] * b[k][j];
}
}
}
}
void printMatrix(int rows, int cols, int matrix[rows][cols]) {
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
printf("%d ", matrix[i][j]);
}
printf("\n");
}
}
int main() {
int rows = 2, cols = 2;
int a[2][2] = { {1, 2}, {3, 4} };
int b[2][2] = { {5, 6}, {7, 8} };
int result[2][2];
printf("Matrix A:\n");
printMatrix(rows, cols, a);
printf("Matrix B:\n");
printMatrix(rows, cols, b);
addMatrices(rows, cols, a, b, result);
printf("Sum of matrices:\n");
printMatrix(rows, cols, result);
subtractMatrices(rows, cols, a, b, result);
printf("Difference of matrices:\n");
printMatrix(rows, cols, result);
multiplyMatrices(rows, cols, a, rows, cols, b, result);
printf("Product of matrices:\n");
printMatrix(rows, cols, result);
return 0;
}
mplement bubble sort, insertion sort, and selection sort.
#include
void bubbleSort(int arr[], int n) {
for (int i = 0; i < n - 1; i++) {
for (int j = 0; j < n - i - 1; j++) {
if (arr[j] > arr[j + 1]) {
int temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
}
void insertionSort(int arr[], int n) {
for (int i = 1; i < n; i++) {
int key = arr[i];
int j = i - 1;
while (j >= 0 && arr[j] > key) {
arr[j + 1] = arr[j];
j--;
}
arr[j + 1] = key;
}
}
void selectionSort(int arr[], int n) {
for (int i = 0; i < n - 1; i++) {
int minIdx = i;
for (int j = i + 1; j < n; j++) {
if (arr[j] < arr[minIdx]) {
minIdx = j;
}
}
int temp = arr[minIdx];
arr[minIdx] = arr[i];
arr[i] = temp;
}
}
void printArray(int arr[], int size) {
for (int i = 0; i < size; i++) {
printf("%d ", arr[i]);
}
printf("\n");
}
int main() {
int arr1[] = {64, 25, 12, 22, 11};
int n = sizeof(arr1) / sizeof(arr1[0]);
printf("Original array:\n");
printArray(arr1, n);
bubbleSort(arr1, n);
printf("Sorted array with Bubble Sort:\n");
printArray(arr1, n);
int arr2[] = {64, 25, 12, 22, 11};
insertionSort(arr2, n);
printf("Sorted array with Insertion Sort:\n");
printArray(arr2, n);
int arr3[] = {64, 25, 12, 22, 11};
selectionSort(arr3, n);
printf("Sorted array with Selection Sort:\n");
printArray(arr3, n);
return 0;
}
Reverse the elements of an array.
#include
void reverseArray(int arr[], int start, int end) {
int temp;
while (start < end) {
temp = arr[start];
arr[start] = arr[end];
arr[end] = temp;
start++;
end--;
}
}
void printArray(int arr[], int size) {
for (int i = 0; i < size; i++) {
printf("%d ", arr[i]);
}
printf("\n");
}
int main() {
int arr[] = {1, 2, 3, 4, 5, 6};
int n = sizeof(arr) / sizeof(arr[0]);
printf("Original array: ");
printArray(arr, n);
reverseArray(arr, 0, n - 1);
printf("Reversed array: ");
printArray(arr, n);
return 0;
}
Find the largest element in a given array.
#include
int findLargest(int arr[], int n) {
int largest = arr[0];
for (int i = 1; i < n; i++) {
if (arr[i] > largest) {
largest = arr[i];
}
}
return largest;
}
int main() {
int arr[] = {12, 34, 56, 78, 99, 23, 45};
int n = sizeof(arr) / sizeof(arr[0]);
printf("The largest element in the array is %d\n", findLargest(arr, n));
return 0;
}
Count the number of vowels in a given string.
#include
#include
#include
int countVowels(char str[]) {
int count = 0;
for (int i = 0; i < strlen(str); i++) {
char c = tolower(str[i]);
if (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u') {
count++;
}
}
return count;
}
int main() {
char str[100];
printf("Enter a string: ");
gets(str);
printf("Number of vowels in the string: %d\n", countVowels(str));
return 0;
}
Concatenate two given strings.
#include
#include
void concatenate(char result[], char str1[], char str2[]) {
int i = 0, j = 0;
// Copy first string
while (str1[i] != '\0') {
result[i] = str1[i];
i++;
}
// Copy second string
while (str2[j] != '\0') {
result[i] = str2[j];
i++;
j++;
}
result[i] = '\0'; // Null-terminate the result
}
int main() {
char str1[100], str2[100], result[200];
printf("Enter the first string: ");
gets(str1);
printf("Enter the second string: ");
gets(str2);
concatenate(result, str1, str2);
printf("Concatenated string: %s\n", result);
return 0;
}
Sort an array of strings alphabetically.
#include
#include
void sortStrings(char arr[][100], int n) {
char temp[100];
for (int i = 0; i < n - 1; i++) {
for (int j = i + 1; j < n; j++) {
if (strcmp(arr[i], arr[j]) > 0) {
strcpy(temp, arr[i]);
strcpy(arr[i], arr[j]);
strcpy(arr[j], temp);
}
}
}
}
void printStrings(char arr[][100], int n) {
for (int i = 0; i < n; i++) {
printf("%s\n", arr[i]);
}
}
int main() {
int n;
printf("Enter number of strings: ");
scanf("%d", &n);
getchar(); // To consume the newline character after entering the number
char arr[n][100];
printf("Enter the strings one by one:\n");
for (int i = 0; i < n; i++) {
gets(arr[i]);
}
sortStrings(arr, n);
printf("Strings in alphabetical order:\n");
printStrings(arr, n);
return 0;
}
Swap the values of two integers using pointers.
#include
void swap(int *a, int *b) {
int temp = *a;
*a = *b;
*b = temp;
}
int main() {
int x, y;
printf("Enter two integers: ");
scanf("%d %d", &x, &y);
printf("Before swapping: x = %d, y = %d\n", x, y);
swap(&x, &y);
printf("After swapping: x = %d, y = %d\n", x, y);
return 0;
}
Dynamically allocate memory for an array and find its sum.
#include
#include
int main() {
int n, *arr, sum = 0;
printf("Enter the number of elements: ");
scanf("%d", &n);
arr = (int *)malloc(n * sizeof(int));
if (arr == NULL) {
printf("Memory not allocated.\n");
return 1;
}
printf("Enter the elements:\n");
for (int i = 0; i < n; i++) {
scanf("%d", &arr[i]);
}
for (int i = 0; i < n; i++) {
sum += arr[i];
}
printf("Sum of elements: %d\n", sum);
free(arr);
return 0;
}
Define a structure for a student and use a pointer to access and modify its members.
#include
struct Student {
char name[50];
int age;
float gpa;
};
void printStudent(struct Student *s) {
printf("Name: %s\n", s->name);
printf("Age: %d\n", s->age);
printf("GPA: %.2f\n", s->gpa);
}
int main() {
struct Student s;
struct Student *ptr = &s;
printf("Enter name: ");
scanf("%s", ptr->name);
printf("Enter age: ");
scanf("%d", &ptr->age);
printf("Enter GPA: ");
scanf("%f", &ptr->gpa);
printStudent(ptr);
return 0;
}
Dynamically allocate memory for a 2D array and perform matrix addition.
#include
#include
int main() {
int rows, cols;
printf("Enter the number of rows and columns: ");
scanf("%d %d", &rows, &cols);
int **matrix1 = (int **)malloc(rows * sizeof(int *));
int **matrix2 = (int **)malloc(rows * sizeof(int *));
int **result = (int **)malloc(rows * sizeof(int *));
for (int i = 0; i < rows; i++) {
matrix1[i] = (int *)malloc(cols * sizeof(int));
matrix2[i] = (int *)malloc(cols * sizeof(int));
result[i] = (int *)malloc(cols * sizeof(int));
}
printf("Enter elements of the first matrix:\n");
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
scanf("%d", &matrix1[i][j]);
}
}
printf("Enter elements of the second matrix:\n");
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
scanf("%d", &matrix2[i][j]);
}
}
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
result[i][j] = matrix1[i][j] + matrix2[i][j];
}
}
printf("Resultant matrix:\n");
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
printf("%d ", result[i][j]);
}
printf("\n");
}
for (int i = 0; i < rows; i++) {
free(matrix1[i]);
free(matrix2[i]);
free(result[i]);
}
free(matrix1);
free(matrix2);
free(result);
return 0;
}
Implement a function to find the length of a string and reverse a string using pointers.
#include
int stringLength(char *str) {
int length = 0;
while (*str != '\0') {
length++;
str++;
}
return length;
}
void reverseString(char *str) {
char *end = str + stringLength(str) - 1;
char temp;
while (str < end) {
temp = *str;
*str = *end;
*end = temp;
str++;
end--;
}
}
int main() {
char str[100];
printf("Enter a string: ");
scanf("%s", str);
printf("Original string: %s\n", str);
reverseString(str);
printf("Reversed string: %s\n", str);
return 0;
}
Define a structure for a student and store multiple student records in an array.
#include
struct Student {
char name[50];
int roll;
float marks;
};
void printStudent(struct Student s) {
printf("Name: %s\n", s.name);
printf("Roll Number: %d\n", s.roll);
printf("Marks: %.2f\n", s.marks);
}
int main() {
int n;
printf("Enter number of students: ");
scanf("%d", &n);
struct Student students[n];
for (int i = 0; i < n; i++) {
printf("Enter details of student %d\n", i + 1);
printf("Name: ");
scanf("%s", students[i].name);
printf("Roll Number: ");
scanf("%d", &students[i].roll);
printf("Marks: ");
scanf("%f", &students[i].marks);
}
printf("\nStudent Details:\n");
for (int i = 0; i < n; i++) {
printStudent(students[i]);
}
return 0;
}
Write student records to a file and then read them back.
#include
struct Student {
char name[50];
int roll;
float marks;
};
int main() {
FILE *file;
struct Student s;
// Writing to file
file = fopen("students.dat", "wb");
if (file == NULL) {
printf("Unable to open file for writing.\n");
return 1;
}
printf("Enter details of the student to write to file\n");
printf("Name: ");
scanf("%s", s.name);
printf("Roll Number: ");
scanf("%d", &s.roll);
printf("Marks: ");
scanf("%f", &s.marks);
fwrite(&s, sizeof(struct Student), 1, file);
fclose(file);
// Reading from file
file = fopen("students.dat", "rb");
if (file == NULL) {
printf("Unable to open file for reading.\n");
return 1;
}
fread(&s, sizeof(struct Student), 1, file);
printf("\nStudent Details from file:\n");
printf("Name: %s\n", s.name);
printf("Roll Number: %d\n", s.roll);
printf("Marks: %.2f\n", s.marks);
fclose(file);
return 0;
}
Append a student record to an existing file and display all records.
#include
struct Student {
char name[50];
int roll;
float marks;
};
int main() {
FILE *file;
struct Student s;
// Appending to file
file = fopen("students.dat", "ab");
if (file == NULL) {
printf("Unable to open file for appending.\n");
return 1;
}
printf("Enter details of the student to append to file\n");
printf("Name: ");
scanf("%s", s.name);
printf("Roll Number: ");
scanf("%d", &s.roll);
printf("Marks: ");
scanf("%f", &s.marks);
fwrite(&s, sizeof(struct Student), 1, file);
fclose(file);
// Reading all records from file
file = fopen("students.dat", "rb");
if (file == NULL) {
printf("Unable to open file for reading.\n");
return 1;
}
printf("\nStudent Details from file:\n");
while (fread(&s, sizeof(struct Student), 1, file)) {
printf("Name: %s\n", s.name);
printf("Roll Number: %d\n", s.roll);
printf("Marks: %.2f\n", s.marks);
printf("\n");
}
fclose(file);
return 0;
}
Update a student's record in the file.
#include
#include
struct Student {
char name[50];
int roll;
float marks;
};
int main() {
FILE *file;
struct Student s;
int rollToUpdate;
int found = 0;
printf("Enter roll number of the student to update: ");
scanf("%d", &rollToUpdate);
file = fopen("students.dat", "rb+");
if (file == NULL) {
printf("Unable to open file for updating.\n");
return 1;
}
while (fread(&s, sizeof(struct Student), 1, file)) {
if (s.roll == rollToUpdate) {
printf("Current details:\n");
printf("Name: %s\n", s.name);
printf("Roll Number: %d\n", s.roll);
printf("Marks: %.2f\n", s.marks);
printf("Enter new details:\n");
printf("Name: ");
scanf("%s", s.name);
printf("Marks: ");
scanf("%f", &s.marks);
fseek(file, -sizeof(struct Student), SEEK_CUR);
fwrite(&s, sizeof(struct Student), 1, file);
found = 1;
break;
}
}
if (!found) {
printf("Student with roll number %d not found.\n", rollToUpdate);
}
fclose(file);
return 0;
}
Delete a student's record from the file.
#include
#include
struct Student {
char name[50];
int roll;
float marks;
};
int main() {
FILE *file, *tempFile;
struct Student s;
int rollToDelete;
int found = 0;
printf("Enter roll number of the student to delete: ");
scanf("%d", &rollToDelete);
file = fopen("students.dat", "rb");
if (file == NULL) {
printf("Unable to open file for reading.\n");
return 1;
}
tempFile = fopen("temp.dat", "wb");
if (tempFile == NULL) {
printf("Unable to open temporary file.\n");
fclose(file);
return 1;
}
while (fread(&s, sizeof(struct Student), 1, file)) {
if (s.roll != rollToDelete) {
fwrite(&s, sizeof(struct Student), 1, tempFile);
} else {
found = 1;
}
}
fclose(file);
fclose(tempFile);
remove("students.dat");
rename("temp.dat", "students.dat");
if (found) {
printf("Student with roll number %d deleted successfully.\n", rollToDelete);
} else {
printf("Student with roll number %d not found.\n", rollToDelete);
}
return 0;
}