C program to check whether triangle is equilateral, scalene or isosceles

Example
Input

Input first side: 30
Input second side: 30
Input third side: 30

Output

Triangle is equilateral triangle

Logic to check equilateral, scalene or isosceles triangle

Step by step descriptive logic to classify triangle as equilateral, scalene or isosceles triangle.

1. Input sides of a triangle from user. Store it in some variables say side1, side2 and side3.
2. Check if(side1 == side2 && side2 == side3), then the triangle is equilateral.
3. If it is not an equilateral triangle then it may be isosceles. Check if(side1 == side2 || side1 == side3 || side2 == side3), then triangle is isosceles.
4. If it is neither equilateral nor isosceles then it scalene triangle.

/**
 * C program to check whether a triangle is Equilateral, Isosceles or Scalene
 */

#include <stdio.h>

int main()
{
    int side1, side2, side3;

    /* Input sides of a triangle */
    printf("Enter three sides of triangle: ");
    scanf("%d%d%d", &side1, &side2, &side3);

    if(side1==side2 && side2==side3) 
    {
        /* If all sides are equal */
        printf("Equilateral triangle.");
    }
    else if(side1==side2 || side1==side3 || side2==side3) 
    {
        /* If any two sides are equal */
        printf("Isosceles triangle.");
    }
    else 
    {
        /* If none sides are equal */
        printf("Scalene triangle.");
    }

    return 0;
}

/*
Output :

Enter three sides of triangle: 30
30
30
Equilateral triangle.
*/