//Passing Fucntions as Arguments

var years = [1990, 1965, 1937, 2005, 1998];

function arrayCalc(arr, fn) {

var arrRes = [];

for(var i = 0; i < arr.length; i++){

arrRes.push(fn(arr[i]));

}

return arrRes;

}

function calculateAge(el) {

return 2016 - el;

}

function isFullAge(el) {

return el >= 18;

}

function maxHeartRate(el){

if(el >= 18 && el <= 81) {

return Math.round(206.9 - (0.67 * el));

} else {

return -1;

}

}

//Here we are not passing calculateAge as a function(i.e calculateAge()) but as a parameter since

//it is a callback function

var ages = arrayCalc(years, calculateAge);

var fullAges = arrayCalc(ages, isFullAge);

var rates = arrayCalc(ages, maxHeartRate);

console.log(ages);

console.log(fullAges);

console.log(rates);