Notes

Write a note in this area. It's really easy to share with others. Click here ...#include <iostream> // Include the library for input and output

using namespace std; // Use the standard namespace to avoid writing 'std::' repeatedly

int main() {
int num; // Declare an integer variable to store the number input by the user
int count = 0; // Initialize a counter to count the number of divisors

cout << "Enter a number: "; // Prompt the user for input
cin >> num; // Take the number input from the user

// Loop through all numbers from 1 to the given number
for (int i = 1; i <= num; i++) {
// Check if 'i' divides 'num' without leaving a remainder
if (num % i == 0) {
count++; // If it divides evenly, increment the count
}
}

// Display the total number of divisors
cout << "The number of divisors of " << num << " is: " << count << endl;

return 0; // End of the program
}

#include <iostream>
using namespace std;

bool isPrime(int num) {
if (num <= 1) return false;
for (int i = 2; i * i <= num; i++) {
if (num % i == 0) return false;
}
return true;
}

void generatePrimes(int limit) {
cout << "Prime numbers up to " << limit << ": ";
for (int i = 2; i <= limit; i++) {
if (isPrime(i)) {
cout << i << " ";
}
}
cout << endl;
}

int main() {
int limit;
cout << "Enter the limit: ";
cin >> limit;

generatePrimes(limit);

return 0;
}
#include <iostream> // This header file allows us to use input-output streams like cin and cout.

using namespace std; // This allows us to use standard C++ functions like cout without having to prefix them with std::.

void primeFactorization(int num) { // Function to find and print the prime factors of 'num'.
// Step 1: Check for the number of 2s that divide 'num'.
while (num % 2 == 0) { // While 'num' is divisible by 2, keep dividing it by 2.
cout << 2 << " "; // Print 2 as one of the prime factors.
num /= 2; // Divide 'num' by 2.
}

// Step 2: Now, 'num' must be odd at this point, so we can skip even numbers.
for (int i = 3; i * i <= num; i += 2) { // Start from 3 and check all odd numbers up to the square root of 'num'.
while (num % i == 0) { // While 'num' is divisible by 'i', keep dividing it by 'i'.
cout << i << " "; // Print 'i' as one of the prime factors.
num /= i; // Divide 'num' by 'i'.
}
}

// Step 3: If 'num' is still greater than 2, then 'num' must be a prime number.
if (num > 2) {
cout << num << " "; // Print the remaining prime factor (if any).
}
}

int main() {
int num; // Declare an integer variable 'num' to store the input number.

cout << "Enter a number: "; // Prompt the user to enter a number.
cin >> num; // Read the input number from the user.

cout << "Prime factors of " << num << " are: "; // Print the message indicating the start of prime factorization.
primeFactorization(num); // Call the function to perform prime factorization.

cout << endl; // Print a newline after the prime factors for better formatting.

return 0; // Return 0 to indicate the successful completion of the program.
}
#include<bits/stdc++.h>
using namespace std;
bool isPrime(int num){
if(num<=1){
return false;
}
for(int i=2;i*i<=num;i++){
if(num%i==0){
return false;
}
}
return true;


}
int main(){
int num;
cin>>num;
if(isPrime(num)){
cout<<num<<"is a prime number:"<<endl;
}
else{
cout<<num<<"is not prime number:"<<endl;
}
return 0;

}
#include<bits/stdc++.h>
using namespace std;
int main(){
int num;
cin>>num;
for(int i=1;i<=num;i++){
if(num%i==0){
cout<<i<<endl;
}
}
return 0;
}