Program in C++ to find largest number using if statement

#include <stdio.h>

int main() {

  double num1, num2, num3;

  printf("Enter first number: ");
  scanf("%lf", &num1);
  printf("Enter second number: ");
  scanf("%lf", &num2);
  printf("Enter third number: ");
  scanf("%lf", &num3);

  // if num1 is greater than num2 & num3, num1 is the largest
  if (num1 >= num2 && num1 >= num3)
    printf("%lf is the largest number.", num1);

  // if num2 is greater than num1 & num3, num2 is the largest
  if (num2 >= num1 && num2 >= num3)
    printf("%lf is the largest number.", num2);

  // if num3 is greater than num1 & num2, num3 is the largest
  if (num3 >= num1 && num3 >= num2)
    printf("%lf is the largest number.", num3);

  return 0;
}

OUTPUT

Enter the first number:400
Enter the second number:50
Enter the third number:30
400 is the largest number.