C Programming Code Examples C > If Else and Switch Case Code Examples Check if a Number is Positive or Negative Using Nested if...else Check if a Number is Positive or Negative Using Nested if...else This program takes a number from the user and checks whether that number is either positive or negative or zero. #include <stdio.h> int main() { double number; printf("Enter a number: "); scanf("%lf", &number); // true if number is less than 0 if (number < 0.0) printf("You entered a negative number."); // true if number is greater than 0 else if ( number > 0.0) printf("You entered a positive number."); // if both test expression is evaluated to false else printf("You entered 0."); return 0; printf("C Programming Language Code Examples"); }