1.
Simple calculator
#include <stdio.h>
void main() {
int num1, num2, choice;
printf("Enter two numbers: ");
scanf("%d %d", &num1, &num2);
printf("Choose operation: \n1. Add \n 2.
Subtract \n 3. Multiply \n 4. Divide\n");
scanf("%d", &choice);
switch(choice) {
case 1:
printf("Result: %d\n", num1 + num2);
break;
case 2:
printf("Result: %d\n", num1 - num2);
break;
case 3:
printf("Result: %d\n", num1 * num2);
break;
case 4:
if (num2 != 0)
printf("Result: %.2f\n", (float)num1 /
num2);
else
printf("Error! Division by zero.\n");
break;
default:
printf("Invalid choice\n");
}
}
Output
Enter two numbers: 3 4
Choose operation:
1. Add
2. Subtract
3. Multiply
4. Divide
3
Result: 12
*********************************
2.smart home
#include <stdio.h>
void main() {
int choice;
printf("Smart Home Control System\n");
printf("1. Turn on Lights\n");
printf("2. Turn off Lights\n");
printf("3. Set AC Temperature\n");
printf("4. Lock Doors\n");
printf("5. Exit\n");
printf("Enter your choice: ");
scanf("%d", &choice);
switch(choice) {
case 1:
printf("Lights turned ON\n");
break;
case 2:
printf("Lights turned OFF\n");
break;
case 3:
printf("Enter desired temperature: ");
int temp;
scanf("%d", &temp);
printf("AC temperature set to %d degree
celcius\n", temp);
break;
case 4:
printf("Doors locked!\n");
break;
case 5:
printf("Exiting Smart Home System...\n");
break;
default:
printf("Invalid choice! Please select a valid
option.\n");
}
Switch -case without break
void main() {
int day;
printf("Enter a number (1-7) for the day of the
week: ");
scanf("%d", &day);
switch(day) {
case 1:
printf("Monday\n");
case 2:
printf("Tuesday\n");
case 3:
printf("Wednesday\n");
case 4:
printf("Thursday\n");
case 5:
printf("Friday\n");
case 6:
printf("Saturday\n");
case 7:
printf("Sunday\n");
default:
printf("Invalid input!\n");
}
}
While
Print 1 to 5
#include <stdio.h>
void main() {
int i = 1;
while (i <= 5)
{
printf("%d\n", i);
i=i+1;
}
Do- while loop
#include <stdio.h>
void main() {
int i = 1;
do {
printf("%d\n", i);
i++;
} while (i <= 5);
}
Hai 10 times using do-while
#include<stdio.h>
void main()
{
int i=1;
do
{
printf("\nhai");
i=i+1;
}while(i<=10);
}
ATM pin
#include <stdio.h>
void main() {
int pin, attempt = 0;
int correctPin = 5566;
do {
printf("Enter your ATM PIN: ");
scanf("%d", &pin);
attempt++;
if (pin == correctPin) {
printf("Access Granted!\n");
break;
} else {
printf("Incorrect PIN. Try again.\n");
}
} while (attempt < 3);
if (attempt == 3 && pin != correctPin) {
printf("Too many failed attempts! Card
blocked.\n");
}
}
For loop- print 1 to 5
#include <stdio.h>
void main()
{
int i;
for (i = 1; i <= 5; i++)
{
printf("%d\n", i);
}
For loop
Sum of N natural numbers
#include <stdio.h>
void main() {
int N, sum = 0;
printf("Enter a number: ");
scanf("%d", &N);
for (int i = 1; i <= N; i++)
{
sum =sum +i;
}
printf("Sum of first %d natural numbers: %d\n",
N, sum);
Factorial of a number
#include <stdio.h>
void main() {
int N, fact = 1;
printf("Enter a number: ");
scanf("%d", &N);
for (int i = 1; i <= N; i++) {
fact=fact*i;
}
printf("Factorial of %d is: %d\n", N, fact);
}
**********************
Reverse of a number
#include <stdio.h>
void main() {
int num, rev = 0, digit;
printf("Enter a number: ");
scanf("%d", &num);
while (num > 0)
{
digit = num % 10; // Extract last digit
rev = rev * 10 + digit; // Append digit to
reversed number
num = num / 10; // Remove last digit
}
printf("Reversed Number: %d\n", rev);
}
Prime number
#include <stdio.h>
#include <math.h> // Necessary for the sqrt
function
void main() {
int n, i, flag= 0;
printf("Enter any number: ");
scanf("%d", &n);
if (n <= 1)
{
printf("%d is not a Prime number.\n", n);
}
else
{
for (i = 2; i <= sqrt(n); i++) {
if (n % i == 0) {
flag=1;
break;
}
}
}
if (flag == 0) {
printf("%d is a Prime number.\n", n);
} else
{
printf("%d is not a Prime number.\n", n);
}
}
Armstrong number
#include <stdio.h>
#include <math.h>
void main() {
int num, original, sum = 0, digits = 0,
remainder;
printf("Enter a number: ");
scanf("%d", &num);
original = num;
while (original != 0) {
digits++;
original = original/ 10;
}
original = num;
while (original != 0) {
remainder = original % 10;
sum = sum+pow(remainder, digits);
original =original/ 10;
}
if (sum == num)
printf("%d is an Armstrong Number\n",
num);
else
printf("%d is not an Armstrong Number\n",
num);
}
Perfect number
#include <stdio.h>
void main() {
int num, i, sum = 0;
printf("Enter a number: ");
scanf("%d", &num);
for (i = 1; i <= num / 2; i++) {
if (num % i == 0)
sum =sum+ i;
}
if (sum == num)
printf("%d is a Perfect Number\n", num);
else
printf("%d is not a Perfect Number\n", num);
Leap year
#include <stdio.h>
void main() {
int year;
// Input: Read a year from the user
printf("Enter a year: ");
scanf("%d", &year);
// Check leap year conditions
if ((year % 4 == 0 && year % 100 != 0) || (year
% 400 == 0)) {
printf("%d is a leap year.\n", year);
} else {
printf("%d is not a leap year.\n", year);
}
}
Output
2000 – leap year
1900-not a leap year
2024 leap year
Leap year 2
#include <stdio.h>
void main() {
int year;
// Input: Read a year from the user
printf("Enter a year: ");
scanf("%d", &year);
if(year%100==0)
{
if (year % 400== 0 )
{
printf("%d is a leap year.\n", year);
}
else
printf("%d is not leap year.\n", year);
}
else
{
if (year%4==0)
{
printf("%d is a leap year.\n", year);
}
else
{
printf("%d is not a leap year.\n", year);
}
}
