C programming, Check if a number is positive or negative.

#include <stdio.h>

int main() {

    double num;

    printf("Enter a number: ");

    scanf("%lf", &num);

    if (num <= 0.0) {

        if (num == 0.0)

            printf("You entered 0.");

        else

            printf("You entered a negative number.");

    } 

    else

        printf("You entered a positive number.");

    return 0;

}