CareerCup

The solution bellow assumes only integers will be used for triangle side length.

An equiliteral triangle has all 3 sides equal
Example 3 3 3

An isosceles trianglle has 2 sides equal
Example 3 2 3

A rightangle triangle has one side squared equal to the sum of the other two sides square (Pythagoras theorem)
Example 3 4 5 (3*3 + 4*4 = 5*5)

static void solution(String fname) {
		if (fname == null) {
			return;
		}
		BufferedReader reader = null;
		FileReader fileReader = null;
		String line = null;
		try {
			fileReader = new FileReader(fname);
			reader = new BufferedReader(fileReader);
			line = reader.readLine();
			while (line != null) {
				int[] sides = parseTriangleData(line);
				displayResult(sides);
				line = reader.readLine();
			}
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			if (fileReader != null) {
				try {
					fileReader.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			if (reader != null) {
				try {
					reader.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}

	static int[] parseTriangleData(String line) {
		if (line == null) {
			return null;
		}
		String[] triangleSides = line.split("\\s+");
		if (triangleSides.length != 3) {
			System.err
					.println("Triangle sides data is corrupt (not equal to 3)");
			return null;
		}
		int[] sides = new int[3];
		for (int i = 0; i < sides.length; i++) {
			sides[i] = Integer.parseInt(triangleSides[i]);
		}
		return sides;
	}

	static void displayResult(int[] sides) {
		if (sides == null) {
			return;
		}
		StringBuilder result = new StringBuilder();
		if (sides[0] == sides[1] && sides[1] == sides[2]) {
			result.append("equilateral");
		} else if (sides[0] == sides[1] || sides[1] == sides[2]
				|| sides[0] == sides[2]) {
			result.append("isosceles");
		}

		if (isRightTriangle(sides)) {
			if(result.length() > 0) {
				result.append(" and ");
			}
			result.append("right-angled");
		}

		if(result.length() == 0) {
			result.append("None");
		}
		
		System.out.println("Triangle is " + result.toString());
	}

	static boolean isRightTriangle(int[] sides) {

		int a_squared = (int) Math.pow(sides[0], 2);
		int b_squared = (int) Math.pow(sides[1], 2);
		int c_squared = (int) Math.pow(sides[2], 2);

		if ((a_squared + b_squared == c_squared)
				|| a_squared + c_squared == b_squared
				|| b_squared + c_squared == a_squared) {
			return true;
		}

		return false;
	}

	public static void main(String[] args) {
		solution("triangle.txt");
	}