C :: Create A Program That Asks User To Input Integer Lengths Of Three Sides Of A Triangle

C programming: I want to creat a program that asks the user to input the integer lengths of three sides of a triangle, and if so whether the triangle is a right-angled, acute or obtuse one. i am having some doubts about the if, else if statements. I never seem to know how and in what order to use them.

Code:

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main(int argc, char *argv[]){
int SideA;
int SideB;
int SideC;
}

[code]....