Intro#

So this problem came in the Computer-Science Introduction Exam. It gives you an array of values equal to either F(emale) or M(ale). You need to return amount of occurances of F and M.

Originally the Exam wanted the examinee to implement this in flowchart, but i’ll implement in javascript instead.

Value Type#

The array could be integer, bool or string. But for simplicity’s sake, we’ll use strings of one character length so either M or F.

Code#

First, start out with a simple loop.

for(var i in arr) {
	var v = arr[i];
}

Then, compare the value to F or M.

for(var i in arr) {
	var v = arr[i];
	if(v == "F") {
	} else if (v == "M") {
	}
}

Oh shoot, we forget to add the variables.

var F = 0;
var M = 0;
for(var i in arr) {
	var v = arr[i];
	if(v == "F") {
	} else if (v == "M") {
	}
}

Oh yeah, increment the variables.

var F = 0;
var M = 0;
for(var i in arr) {
	var v = arr[i];
	if(v == "F") {
		F++
	} else if (v == "M") {
		M++;
	}
}

Finally, wrap it in a nice beautiful function.

function solve(arr) {
	var F = 0;
	var M = 0;
	for(var i in arr) {
		var v = arr[i];
		if(v == "F") {
			F++
		} else if (v == "M") {
			M++;
		}
	}
	
	return {F: F, M: M};
}
// solve(["F", "M", "M", "M", "F", "F", "F", "F", "M", "F"])
// should output: {F: 6, M: 4}

Google Chrome Console Output

Bonus#

Automate this function to calculate unspecified occurances of string in the array. Return the occurances in an Object.

function solve(arr) {
	var obj = {};
	
	for(var i in arr) {
		var v = arr[i];
		if(obj[v] === undefined) {
			obj[v] = 0 ;
		}
		
		obj[v]++;
	}
	
	return obj
}
// solve(["U", "M", "M", "M", "F", "F", "F", "F", "M", "U"])
// should output: {U: 2, M: 4, F: 4}