Problem : Counter 2 | #2665 | LeetCode
Write a function createCounter. It should accept an initial integer init. It should return an object with three functions.
The three functions are:
1. increment() increases the current value by 1 and then returns it.
2. decrement() reduces the current value by 1 and then returns it.
3. reset() sets the current value to init and then returns it.
Example 1:
Input: init = 5, calls = ["increment","reset","decrement"]
Output: [6,5,4]
Explanation:
const counter = createCounter(5);
counter.increment(); // 6
counter.reset(); // 5
counter.decrement(); // 4
Example 2:
Input:
init = 0, calls = ["increment", "increment", "decrement", "reset", "reset"]
Output: [1,2,1,0,0]
Explanation:
const counter = createCounter(0);
counter.increment(); // 1
counter.increment(); // 2
counter.decrement(); // 1
counter.reset(); // 0
counter.reset(); // 0
Solution:
/**
* @param {integer} init
* @return { increment: Function, decrement: Function, reset: Function }
*/
var createCounter = function(init) {
var current = init;
return {
increment: function() {
current += 1;
return current;
},
decrement: function() {
current -= 1;
return current;
},
reset: function() {
current = init;
return current;
}
}
};
/**
* const counter = createCounter(5)
* counter.increment(); // 6
* counter.reset(); // 5
* counter.decrement(); // 4
*/
Explanation:
Here's an explanation of the code step by step:
1. We define the `createCounter` function, which takes an initial integer `init` as a parameter.
2. Inside the `createCounter` function, we create a variable `current` and set it to the initial value `init`. This variable will hold the current value of the counter.
3. We return an object with three functions: `increment`, `decrement`, and `reset`.
4. The `increment` function increases the `current` value by 1 and then returns the updated `current` value.
5. The `decrement` function reduces the `current` value by 1 and then returns the updated `current` value.
6. The `reset` function sets the `current` value back to the initial value `init` and then returns the updated `current` value.
7. Finally, we demonstrate the usage of the `createCounter` function by creating a counter with an initial value of 5 and calling the three functions on it, printing the results to the console.