← IGCSE Computer Science Paper 1

Using digital currency to send money to other people

Sending digital currency straight from one person's wallet to another's over the internet, even in another country, using the receiver's wallet address. No coins or notes are posted.

Part of: IGCSE Computer Science 0478 — 5.2 Digital Currency — Module 8

Understanding Using digital currency to send money to other people in IGCSE Computer Science Paper 1

What it does: The transfer goes straight to a wallet in another country over the internet. Nothing physical is posted. The friendAddress value is the receiver's wallet address, which the sender must supply to complete the person to person transfer.

Common mistakes: Digital currency is sent to the receiver's wallet address, not a postal address. Line 1 should be INPUT walletAddress. The sender can only send an amount that is less than or equal to their balance. The test should be amount <= balance.

Class: _____________________ · Name: _____________________ · Date: _________

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This module's key terms are also in a printable crossword (Modules 500–509) and word search (Modules 490–509).

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Learning

Duo

Maya in the UK wants to send digital currency to her cousin in Kenya. What does she need to send it?

Her cousin's home postal addressHer cousin's wallet address

Matches

post(coins, friendAddress)

↓

Digital currency has no coins or notes to post. It is sent over the internet from wallet to wallet, not delivered by post.

Applying

Meanings

Term

peer-to-peer transfer

Meaning

Sending digital currency straight from one person's wallet to another's over the internet, even in another country, using the receiver's wallet address. No coins or notes are posted.

Practice

INPUT receiverAddress

Testing

Gaps

(0.5, receiverAddress)

Check Answer

Spots

1INPUT postalAddress

2INPUT amount

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Quick Questions

1. Maya in the UK wants to send digital currency to her cousin in Kenya. What does she need to send it?

A. Her cousin's wallet address ✓

B. Her cousin's home postal address

Digital currency is sent to a wallet address. Nothing is posted to a house, so a postal address is not needed.

2. Which statement about sending digital currency to a friend is correct?

A. It is sent over the internet from one wallet to another ✓

B. The sender must post coins or notes to the friend

Digital currency has no coins or notes. It is a digital record that is sent from wallet to wallet over the internet.

3. Can digital currency be sent to someone in another country?

A. No, it can only be sent within the same country

B. Yes, the internet connects both wallets wherever they are ✓

Because the transfer happens over the internet, the sender and receiver can be in different countries.

4. A person-to-person transfer of digital currency means:

A. Money must be handed over face to face

B. Money goes straight from one person's wallet to another's ✓

Person-to-person (peer-to-peer) means the sender and receiver deal directly, and they do not need to meet.

5. Sam sends digital currency to Ana but types the wrong wallet address. What is the likely result?

A. The money goes to the wrong wallet ✓

B. The money still reaches Ana because it knows who she is

The wallet address decides where the money goes. A wrong address sends it to a different wallet, so the sender must check it carefully.

Match the Pairs

send(walletA, walletB, 5) → Send 5 units of digital currency from one person's wallet directly to another person's wallet over the internet

receiverAddress = "7xK92fQ" → The receiver's wallet address, which the sender needs so the digital currency goes to the right person

Digital currency can be sent to a person in another country over the internet, with no need to post anything → send(myWallet, walletInKenya, 20)

The sender must have the receiver's wallet address before a transfer can be made → send(myWallet, friendAddress, 10)

post(coins, friendAddress) → Digital currency has no coins or notes to post. It is sent over the internet from wallet to wallet, not delivered by post.

send(myWallet, "Sam", 15) → The transfer uses the receiver's name instead of their wallet address, so the system cannot tell which wallet should receive the money.

Key Term

peer-to-peer transfer

Sending digital currency straight from one person's wallet to another's over the internet, even in another country, using the receiver's wallet address. No coins or notes are posted.

Fill in the Blanks

1. send(0.5, receiverAddress)

Hint: Type the function name that transfers digital currency from your wallet to another person's wallet.

2. receiverAddress ← "x9K4"

Hint: Type the variable name that stores the wallet address of the person receiving the money.

3. country ← "Japan" IF country ≠ "UK" THEN OUTPUT "Sent to another country"

Hint: Type the comparison operator meaning 'is not equal to', to check the receiver is in a different country.

4. sendByPost ← FALSE send(2.5, receiverAddress) OUTPUT "Sent over the internet"

Hint: Type the Boolean value showing that no coins or notes are posted.

5. IF receiverAddress = "" THEN OUTPUT "Address needed" ENDIF

Hint: Type the keyword that follows the condition when checking that the receiver's wallet address is missing.

Spot the Error

Question 1

A INPUT postalAddress

B INPUT amount

C SEND amount TO walletAddress

D OUTPUT "Sent"

Line A — Digital currency is sent to the receiver's wallet address, not a postal address. Line 1 should be INPUT walletAddress.

Question 2

A balance ← 50

B amount ← 20

C IF amount >= balance THEN

D SEND amount TO address

E ENDIF

Line C — The sender can only send an amount that is less than or equal to their balance. The test should be amount <= balance.

Question 3

A address ← "WX91-KL20"

B amount ← 15

C country ← "Japan"

D SEND amount TO country

E OUTPUT "Sent to " + country

Line D — Money is sent to the receiver's wallet address, not to a country name. Line 4 should be SEND amount TO address.

Question 4

A INPUT amount

B INPUT address

C POST coins TO address

D OUTPUT "Sent"

Line C — No coins or notes are posted. The digital amount is sent over the internet, so line 3 should be SEND amount TO address.

Question 5

A INPUT address

B IF address <> "" THEN

C OUTPUT "Address needed"

D ENDIF

Line B — The warning should only appear when the wallet address is missing (empty). The test should be address = "".

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