diceProbability.js

/* Program to find probability for rolling of two dies for getting sums of die faces which are either less than or greater than or equal to given number */

const validateData = (input) => {
  const result = input.match(/^[<|>|=][1-6]$/);
  return result != null ? true : false;
};

const checkProbability = (sign, number) => {
  let resultList = [];
  let noOfExhaustiveEvent = 0; // this means our favorable event.

  for (let i = 1; i <= 6; i++) {
    for (let j = 1; j <= 6; j++) {
      if (eval(`${i + j} ${sign} ${number}`)) {
        resultList.push({ data: `(${i}, ${j})` });
        noOfExhaustiveEvent++;
      }
    }
  }

  return { ...resultList, noOfExhaustiveEvent };
};

const evaluateProbability = (input) => {
  const isValid = validateData(input);
  if (isValid) {
    const result = checkProbability(input.split("")[0], input.split("")[1]);
    console.log(
      result,
      "Probability is : " +
        parseFloat(result.noOfExhaustiveEvent / 36).toFixed(2)
    );
  } else
    console.log(
      "invalid input format ; try using >5 where signs are > , < or = and numbers are from 1 to 6"
    );
};

//Example:
evaluateProbability(">3"); //getting more than 3
evaluateProbability("=5"); // sum equal to five
evaluateProbability(">7"); // sum greater than 7

// (1,1), (1,2), (1,3), (1,4), (1,5), (1,6)
// (2,1), (2,2), (2,3), (2,4), (2,5), (2,6)
// (3,1), (3,2), (3,3), (3,4), (3,5), (3,6)
// (4,1), (4,2), (4,3), (4,4), (4,5), (4,6)
// (5,1), (5,2), (5,3), (5,4), (5,5), (5,6)
// (6,1), (6,2), (6,3), (6,4), (6,5), (6,6)


//author : Saroj Dahal
//code : 2021 Oct 26