jevit01/functions_and_scope_assignment

Function Exercies

NOTE: I am not asking for a specific ES syntax, but please note that you need to be able to do both.

1. What will the following code log? Why?

let greeting = 'hi'

function hello(){
greeting = 'bye'
}

hello()
console.log(greeting)

it will log 'bye' because greeting was changed after the function.

2. Write a function that returns the largest of two numbers. If they are equal, return the second one.

function largest(num1, num2){

 if (num1 > num2){
   return num1;
 } else {
   return num2;

 }
}
console.log(largest(9,6));

3. Write a function named getDogAge that takes one argument: a dog's age in human years. The function returns the dog's age in dog years. The conversion rate is 1 human year to 7 dog years.

   • Call the function and log the result.

function getDogAge(dogAge){
return 7 * dogAge;

}
console.log(getDogAge(2));

4. Create two functions that calculate properties of a circle, using the definitions here

• Create a function called calcCircumfrence that takes the radius as an argument and return the circumference. Call the function and log the circumference:

function calcCircumfrence(radius){
return Math.PI * 2 * radius;

}
console.log('Circumfrence ' + calcCircumfrence(2));

• Create a function called calcArea that takes the radius as an argument and returns the area.

function calcArea(radius){
  return Math.PI * radius * radius;

}

console.log('Area ' + calcArea(3));

Create a third function circleProps that takes the radius as an argument, calls the two other functions, and logs the area and circumference. The output should look like this:

"The circumference is ___".

"The area is ___".

function circleProps(radius){
  return 'The circumference is ' + calcCircumfrence(radius) +'\nThe area is ' +  calcArea(radius);
}
console.log(circleProps(1));

5. Make a temperature converter. Use google to find the conversion formulas.

• Create a function called celciusToFahrenheit that takes a temperature in Celsius and returns it in Fahrenheit.

function celciusToFahrenheit(temp){
  return temp * 1.8 + 32
}
console.log(Math.round(celciusToFahrenheit(32)));

• Create a function called fahrenheitToCelcius that takes a temperature in Fahrenheit and returns it in Celsius.

function fahrenheitToCelcius(temp){
  return (temp - 32)* 5/9
}
console.log(Math.round(fahrenheitToCelcius(80)));

• Create a function called convertTemperature that takes two arguments: a temperature and a string. If the string is 'C', use fahrenheitToCelcius to return the temperature to Celsius. If the string is 'F', use celciusToFahrenheit to convert the temperature to Fahrenheit.

function convertTemperature(temp, inp){
  if (inp === 'C'){
    return temp * 1.8 + 32
  } else if (inp === 'F'){
    return (temp - 32)* 5/9
  } else {
    return 'You didnt input anything'
  }
}
console.log(convertTemperature(32,'C'));

6. The Calculator:

• Write a function square that returns the square of a number.

function square(num){
  return num * num
}
console.log(square(4));

• Write a function half that returns half the value of a number.

function half(num){
  return num / 2
}
console.log(half(10));

• Write a function percentOf that takes two numbers. Calculate what percent the first number is of the second number, and return the result as a string. For example, 2 is 50% precent of 4, so the function returns '50%'.

function percentOf(num, num1){
  let raw = (num / num1) * 100
  return raw.toFixed(0) + '%'

}
console.log(percentOf(2,3));

• Write a function called areaOfCircle that takes one argument (the radius), and return the area of a circle with that radius.

function calcArea(radius){
  return Math.PI * radius * radius;

}

console.log('Area ' + calcArea(3));

• Bonus: Round the result so there are only two digits after the decimal.

function calcArea(radius){
  return (Math.PI * radius * radius).toFixed(2);

}

console.log('Area ' + calcArea(3));

• Write a function doStuff that takes one argument (a number) and does the following (using the functions you wrote earlier):
  1. Calculates and saves the square of the number.
  2. Calculates and saves half the value of the result of #1.
  3. Calculate the area of a circle with the result of #2 as the radius.
  4. Calculate and returns the percentage the squared result (#1) is of the area (#3)

function square(num){ return num * num } function half(num){ return num / 2 } function calcArea(radius){ return (Math.PI * radius * radius).toFixed(2);

} function percentOf(num, num1){ let raw = (num / num1) * 100 return raw.toFixed(0) + '%'

}

function doStuff(num){ let squareNum = square(num); let halved = half(squareNum); let circleArea = calcArea(halved); console.log('The area of the circle is ' + circleArea); return percentOf(squareNum, circleArea); }

console.log(doStuff(5));

  ```

7. Write a function arraySum that takes in one argument and returns the sum of all the elements.

function arraySum(arr){
  let result = 0;
  for(let i = 0; i < arr.length; i++){
    result += arr[i];
  }
  return result;
}
console.log(arraySum([2,1,2,3,4]));