Loop Examples for CIS110

loopExampesForCIS110.js

// While Loop
var canGraduate = false;
// The while loop will execute the logic within as long as the logical condition is true
// In this example we're evaluating the negated (!) value of canGraduate
// Negating means that your flipping a false to true and vice-versa.
while (!canGraduate) {
  passNextCourse();
  //In this scenario, when you've met all the requirements for graduation
  //This expression will set the value of canGraduate to true
  canGraduate = haveIMetTheRequirementsForGraduation();
}
graduate();

// For Loop in it's simplest form
var coursesINeedToGraduate = 15;
// The for loop declaration has three important segments, these are seperated by (;):
// Segment: 1: Initialize your "counter" => mycourseCounter = 0
// Segment: 2: Loop condition, if this expression evaluates to true 
//              then the logic contained within the loop will be executed
// Segment: 3: Incrementer, This simply adds 1 for every loop
//              Everytime you pass a class the myCourseCounter will increase by 1
// The (++) operator works across many languages, but all it does is increment a variable by 1
for (var myCourseCounter = 0; myCourseCounter < coursesINeedToGraduate; myCourseCounter++) {
  passNextCourse();
}
graduate();

// ForEach
// I'm initializing an array (collection) here of courses I need to take to graduate
var coursesINeedToPass = ['CIS175', 'CIS110', 'SOC450', 'MAT311'];
// I'm using a forEach loop to iterate over each item in the array
coursesINeedToPass.forEach(course =>{
  //This logic will be executed for each course 
  passNextCourse(course);
  console.log(`Yay I passed ${course}!`);
});

// ForIn Loop
// I'm initializing an array (collection) here of courses I need to take to graduate
var coursesINeedToPass = ['CIS175', 'CIS110', 'SOC450', 'MAT311'];
// I'm using a forIn loop to iterate over each item in the array
for (course in coursesINeedToPass){
  //This logic will be executed for each course 
  passNextCourse(course);
  console.log(`Yay I passed ${course}!`);
};

// Recursive loop
var coursesINeedToGraduate = 15;
function passCoursesUntilICanGradate(){
  // The decrement operator (--), the exact opposite of the increment operator
  // Subtracts 1 from the variable every single time
  coursesINeedToGraduate--;
  // Here I'm checking if I have to take any additional courses
  if (coursesINeedToGraduate > 0){
    //Here my function is calling itself (it's recursive)
    passCoursesUntilICanGradate();
  }
  //If I have no more courses to take
  else {
    // I'm essentially exiting the loop here and GRADUATING!!!
    graduate();
  }
}

// Bad ForEach 
var coursesINeedToPass = ['CIS175', 'CIS110', 'SOC450', 'MAT311']; 
coursesINeedToPass.forEach(course => { 
  // I hate Sociology so I want to switch it with a Math course
  if (course.startsWith('SOC')){
    // Here I'm adding an item to the coursesINeedToPass array (collection)
    // This is not allowed in many languages
    coursesINeedToPass.push('MAT600');
    continue;
  }
  passNextCourse(course);

  console.log(`Yay I passed ${course}!`);
});