christmastree.c

string christmasTree(int height){
	string output = "";
	if(height >= 0 && height <= 100){
		int numStars = 1;
		for(int lines=height; lines > 0; lines--){
			for(int spaces=(lines-1); spaces > 0; spaces--){
				output += " ";
			}
			for(int star=0; star < numStars; star++){
				output += "*";
			}
			numStars += 2;
			output += "\n";
		}
	}
	return output;
}

christmastree.go

package main

import "fmt"

func main() {
	fmt.Println(christmasTree(100))
}

func christmasTree(height int) (output string){
  if height >= 0 && height <= 100 {
    numStars := 1
    for lines := height; lines > 0; lines-- {
      for spaces := (lines -1); spaces > 0; spaces-- {
        output += " "
      }
      for star :=0; star < numStars; star++ {
        output += "*"
      }
      numStars += 2
      output += "\n"
    }
  }
  return
}

christmastree.js

function christmasTree(height) {
  var output = "";
  if(height >= 0 && height <= 100){
    var numStars = 1;
    for(var lines=height; lines > 0; lines--){
      for(var spaces = (lines -1); spaces > 0; spaces--){
        output += " ";
      }
      for(var star=0; star < numStars; star++){
        output += "*";
      }
      numStars += 2;
      output += "\n";
    }
  }
  return output;
}