beginner coding problem and code solution c and c++

Print out a “Greetings!” message.

#include <stdio.h>

int main() {
  printf("Greetings!\n");
  return 0;
}

Create a program that converts meters to feet.

#include <stdio.h>

int main() {
  float meters;
  printf("Enter a measurement in meters: ");
  scanf("%f", &meters);

  float feet = meters * 3.28084;
  printf("%f meters is equal to %f feet.\n", meters, feet);

  return 0;
}

Program a temperature conversion tool.

#include <stdio.h>

int main() {
  float temperature;
  char unit;

  printf("Enter a temperature: ");
  scanf("%f %c", &temperature, &unit);

  if (unit == 'C') {
    float fahrenheit = temperature * 9 / 5 + 32;
    printf("%f degrees Celsius is equal to %f degrees Fahrenheit.\n", temperature, fahrenheit);
  } else if (unit == 'F') {
    float celsius = (temperature - 32) * 5 / 9;
    printf("%f degrees Fahrenheit is equal to %f degrees Celsius.\n", temperature, celsius);
  } else {
    printf("Invalid unit.\n");
  }

  return 0;
}

Create a program that calculates the area of a circle.

#include <stdio.h>

int main() {
  float radius;
  printf("Enter the radius of a circle: ");
  scanf("%f", &radius);

  float area = 3.14159 * radius * radius;
  printf("The area of the circle is %f.\n", area);

  return 0;
}

Create a program that calculates the volume of a sphere.

#include <stdio.h>

int main() {
  float radius;
  printf("Enter the radius of a sphere: ");
  scanf("%f", &radius);

  float volume = 4 / 3 * 3.14159 * radius * radius * radius;
  printf("The volume of the sphere is %f.\n", volume);

  return 0;
}

Create a program that determines whether a number is prime.

#include <stdio.h>

int main() {
  int number;
  printf("Enter a number: ");
  scanf("%d", &number);

  int isPrime = 1;
  for (int i = 2; i <= number / 2; i++) {
    if (number % i == 0) {
      isPrime = 0;
      break;
    }
  }

  if (isPrime) {
    printf("%d is a prime number.\n", number);
  } else {
    printf("%d is not a prime number.\n", number);
  }

  return 0;
}