CHAR questions

`String.prototype.charAt` returns the character at a specified index in a string. If the index is out of range, it returns an empty string. 

const str = 'hello';
const char = str.charAt(1);
console.log(char); // 'e'

`String.fromCharCode` returns a string created from the specified sequence of UTF-16 code units. It is used to convert code units to characters. 

const char = String.fromCharCode(65);
console.log(char); // 'A'

When a customer disputes a charge, it results in a chargeback. Stripe provides tools to help you manage chargebacks through the Dashboard. You can review chargeback details, submit evidence to contest the dispute, and track the outcome. If you win the dispute, the chargeback amount is refunded to your account. Stripe charges a fee for each chargeback, which is deducted from your account.

Stripe helps manage chargebacks by providing detailed information and tools to respond to disputes. When a chargeback occurs, Stripe notifies you via the Dashboard, where you can view the details of the dispute and submit evidence to contest it. Stripe offers guidance on what evidence to provide and tracks the progress of the dispute. If you win the dispute, the chargeback amount is refunded to your account. Stripe charges a fee for each chargeback, which is deducted from your balance.

Stripe's fees depend on the payment method and location. Typically, Stripe charges a percentage of the transaction amount plus a fixed fee per transaction. For example, in the U.S., the standard fee is 2.9% + 30¢ per successful card charge. Additional fees apply for international transactions, currency conversions, and certain features like advanced fraud protection or on-demand payouts. Detailed fee information is available on the Stripe website and can be reviewed in your account settings.

Use a hash map to count the frequency of each character, then iterate through the string to find the first character with a count of 1. For example, in 'swiss', the first non-repeating character is 'w'.

XML has several key features: 1. Simplicity: It is easy to understand and read. 2. Extensibility: You can define your own tags. 3. Structure: Data is stored in a hierarchical format. 4. Platform independent: It can be used across different systems. 5. Human and machine-readable: XML is easily readable by both humans and machines. 6. Self-descriptive: Tags describe the data they enclose. 

 <person>
  <name>John</name>
  <age>30</age>
</person>