Conditional statements are used to decision based on different conditions.
By default , statements in JavaScript script executed sequentially from top to bottom. If the processing logic require so, the sequential flow of execution can be altered in two ways:
- Conditional execution: a block of one or more statements will be executed if a certain expression is true
- Repetitive execution: a block of one or more statements will be repetitively executed as long as a certain expression is true. In this section, we will cover _if_, _else_ , _else if_ statements. The comparison and logical operator we learned in the previous sections will be useful in here.
Conditions can be implementing using the following ways:
In JavaScript and other programming languages the key word _if_ use to check if a condition is true and to execute the block code. To create an if condition, we need _if_ keyword, condition inside a parenthesis and block of code inside a curly bracket({}).
```js
// syntax
if (condition) {
//this part of code run for truthy condition
}
```
**Example:**
```js
let num = 3
if (num > 0) {
console.log(`${num} is a positive number`)
}
// 3 is a positive number
```
```js
let isRaining = true
if (isRaining) {
console.log('Remember to take your rain coat.')
}
```
As you can see in the above condition, 3 is greater than 0 and it is a positive number. The condition was true and the block code was executed. However, if the condition is false, we do not see a result. The same goes for the second condition, if isRaining is false the if block will not be executed and we do not see an output. In order to see the result of the falsy condition, we should have another block, which is going to be _else_.
On our daily life, we make decision on daily basis. We make decision not by checking one or two conditions instead we make decisions based on multiple conditions. As similar to our daily life, programming is also full conditions. We use *else if* when we have multiple conditions.
Switch is an alternative for **if else if else else**.
The switch statement starts with a switch keyword followed by a parenthesis and code block. Inside the code block we will have different cases. Case block run if the value in the switch statement parenthesis match with the case vale. The break is to terminate and it does not go down after the condition is satisfied. The default block run if all the cases don't satisfy the condition.
🌕 You are extraordinary and you have a remarkable potential. You have just completed day 4 challenges and you are four steps a head in to your way to greatness. Now do some exercises for your brain and for your muscle.
1. Get user input using prompt(“Enter your age:”). If user is 18 or older , give feedback:You are old enough to drive but if not 18 give feedback to wait for the years he supposed to wait for.
```sh
Enter your age: 30
You are old enough to drive.
Enter your age:15
You are left with 3 years to drive.
```
1. Compare the values of myAge and yourAge using if … else. Based on the comparison log to console who is older (me or you). Use prompt(“Enter your age:”) to get the age as input.
