Check Valid Triangle in Java
beginner· Control Flow · Conditional Statements
Problem
The triangle inequality theorem says a triangle can only exist when the sum of any two sides is strictly greater than the third.
Given three side lengths, determine whether they can form a valid triangle.
Input
a = 7, b = 10, c = 5
Output
Valid triangle: true
Java Program
Java
public class ValidTriangle {
public static void main(String[] args) {
int a = 7, b = 10, c = 5;
boolean isValid = (a + b > c) && (b + c > a) && (a + c > b); // all three pairwise checks must hold
System.out.println("Valid triangle: " + isValid);
}
}Output
Valid triangle: true
Core Logic
Checking all three pairwise sums against the remaining side confirms the triangle inequality holds in every direction, not just one.
How It Works
- 1
a + b > cchecks the inequality for the first pair against the third side. - 2
b + c > aanda + c > bcheck the remaining two pairs the same way. - 3
&&combines all three checks — the sides form a valid triangle only if none of them fail.
For
7, 10, 5: 7+10=17>5, 10+5=15>7, and 7+5=12>10 — all three hold, so the triangle is valid.💡
Key Point: All three pairwise checks are necessary — checking only one or two could pass a set of sides that fails the inequality on the pair you didn't check.
Key Concepts
triangle inequalitylogical ANDboolean expression