Skip to main content

C Program to Check Whether a Number is Positive or Negative

C Program to Check Whether a Number is Positive or Negative

In this example, you will learn to check whether a number (entered by the user) is negative or positive. 
 
Positive and negative numbers in a number line
To understand this example, you should have the knowledge of following C programming topics:
This program takes a number from the user and checks whether that number is either positive or negative or zero.

Example #1: Check if a Number is Positive or Negative Using if...else

#include <stdio.h>
int main()
{
    double number;

    printf("Enter a number: ");
    scanf("%lf", &number);

    if (number <= 0.0)
    {
        if (number == 0.0)
            printf("You entered 0.");
        else
            printf("You entered a negative number.");
    }
    else
        printf("You entered a positive number.");
    return 0;
}
You can also solve this problem using nested if else statement.

Example #2: Check if a Number is Positive or Negative Using Nested if...else

#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;
}
Output 1
Enter a number: 12.3
You entered a positive number.
Output 2
Enter a number: 0
You entered 0.

Comments

Popular posts from this blog

C Program to Find all Roots of a Quadratic Equation

C Program to Find all Roots of a Quadratic Equation This program accepts coefficients of a quadratic equation from the user and displays the roots (both real and complex roots depending upon the discriminant ).   To understand this example, you should have the knowledge of following C programming topics: C Programming Operators C if...else Statement The standard form of a quadratic equation is: ax 2 + bx + c = 0, where a, b and c are real numbers and a ≠ 0 The term b 2 -4ac is known as the discriminant of a quadratic equation. The discriminant tells the nature of the roots. If discriminant is greater than 0, the roots are real and different. If discriminant is equal to 0, the roots are real and equal. If discriminant is less than 0, the roots are complex and different. Example: Program to Find Roots of a Quadratic Equation #include <stdio.h> #include <math.h> int main () ...

C Program to Check Leap Year

C Program to Check Leap Year This program checks whether an year (integer) entered by the user is a leap year or not.   To understand this example, you should have the knowledge of following C programming topics: C Programming Operators C if...else Statement A leap year is exactly divisible by 4 except for century years (years ending with 00). The century year is a leap year only if it is perfectly divisible by 400. Example: Program to Check Leap Year #include <stdio.h> int main () { int year ; printf ( "Enter a year: " ); scanf ( "%d" ,& year ); if ( year % 4 == 0 ) { if ( year % 100 == 0 ) { // year is divisible by 400, hence the year is a leap year if ( year % 400 == 0 ) printf ( "%d is a leap year." , year ); else printf ( "%d i...

C Program to Find ASCII Value of a Character

C Program to Find ASCII Value of a Character In C programming, a character variable holds ASCII value (an integer number between 0 an 127) rather than character itself. You will learn how to find ASCII value of a character in this program.   To understand this example, you should have the knowledge of following C programming topics: C Programming Data Types C Programming Constants and Variables C Input Output (I/O) A character variable holds ASCII value (an integer number between 0 and 127) rather than that character itself in C programming. That value is known as ASCII value. For example , ASCII value of 'A' is 65. What this means is that, if you assign 'A' to a character variable, 65 is stored in that variable rather than 'A' itself. Program to Print ASCII Value #include <stdio.h> int main () { char c ; printf ( "Enter a character: " ); // Re...