What are the Best Solidity Smart Contract Examples?

The
growth
of

blockchain
technology
has
invited
attention
to
many
significant
advancements.
Cryptocurrencies
made
their
presence
felt
in
the
financial
markets
worldwide,
and
blockchain
technology
made
headlines
everywhere.
Was
blockchain
limited
to
cryptocurrencies
only?
No,
different

blockchain
platforms
were
working
on
their
unique
and
innovative
offerings. 

Any
smart
contract
code
example
can
help
you
understand
how
smart
contract
functionality
changed
the
blockchain
landscape
permanently.
Developers
can
leverage

smart
contracts
to
come
up
with
complex
applications
that
follow
the
decentralized
approach.

Solidity
is
one
of
the
most
popular
programming
languages
for
creating
smart
contracts,
especially
for

Ethereum.
Interestingly,
Solidity
ensures
that
smart
contract
functionality
is
universally
available.
Let
us
learn
about
different
examples
of
Solidity
smart
contract
code
and
their
significance.

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your
identity
as
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certified
blockchain
expert
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Why
Should
You
Learn
the
Examples
of
Solidity
Smart
Contracts?

You
must
be
wondering
why
you
must
learn
the
examples
of
smart
contracts
in
Solidity.
The
best
reason
to
learn
Solidity
smart
contract
examples
is
the
power
that
Ethereum
holds
over
the
blockchain
industry.
Ethereum
was
the
first
blockchain
to
introduce
smart
contract
programmability
with
the
help
of
Solidity.

Programming
smart
contracts
on
Ethereum
was
not
as
easy
as
it
is
now
because
only
a
few
programmers
were
fluent
in
the

EVM
architecture.
Solidity
emerged
as
a
promising
solution
to
help
developers
in
the
construction
of

decentralized
applications.
The
first
version
of
Solidity
was
launched
in
2021
and
has
been
serving
as
a
major
force
for
transformation
of
smart
contract
development
experience
for
users. 

Solidity
helped
in
solving
many
problems
associated
with
smart
contract
development,
such
as
compatibility
and
scalability.
The
best
Solidity
smart
contract
examples
can
show
you
how
Solidity
has
reduced
the
overall
difficulty
in
smart
contract
development
process.
Smart
contract
development
with
conventional
programming
languages
was
a
clumsy
and
complex
process.

Solidity
served
as
the
next
big
solution
for
simplification
of
smart
contract
development.
It
has
removed
complexity
by
ensuring
a
direct
association
of
its
syntax
and
structure
with
EVM.
Solidity
ensures
translation
of
written
code
to
EVM
codes,
thereby
ensuring
better
convenience
for
developers.

Curious
to
understand
the
complete
smart
contract
development
lifecycle?
Enroll
now
in
the Smart
Contracts
Development
Course

Discovering
the
Components
of
Smart
Contract
Code
in
Solidity

The
importance
of
Solidity
for
smart
contract
development
provides
a
clear
impression
of
the
reasons
for
its
popularity.
You
must
be
curious
about
queries
like
“How
do
you
write
a
smart
contract
in
Solidity?”
after
learning
the
importance
of
Solidity.
The
code
of
Solidity
has
to
be
encapsulated
in
contracts.

Smart
contracts
or
contracts
in
Solidity
include
a
collection
of
code
or
its
relevant
functions
and
data
or
its
relevant
state,
residing
at
a
particular
address
on
Ethereum
blockchain.
Contracts
serve
as
fundamental
blocks
for
application
development
on
Ethereum.
Here
are
two
examples
of
Solidity
smart
contract
codes
that
can
give
you
a
basic
idea
of
how
they
work
and
the
components
in
Solidity
code. 

Learn
about
the
fundamentals
of
smart
contracts
and
solidity
with

Solidity
&
Smart
Contracts
E-Book

Basic
Solidity
Smart
Contract 

The
best
Solidity
contract
example
to
start
with
is
a
simple
example
like
the
‘helloWorld’
examples
for
other
programming
languages.
Here’s
what
a
simple,
smart
contract
looks
like
in
Solidity.

pragma solidity ^0.5.0; contract firstContract {  function helloWorld () public pure returns (string) {  return "HelloWorld !. This is your first Contract";  } }

The
code
example
features
one
method,
“helloWorld
().”
The
method
returns
the
“HelloWorld
!.
This
is
your
first
Contract”
string
as
the
output.

Excited
to
learn
about
the
critical
vulnerabilities
and
security
risks
in
smart
contract
development,
Enroll
now
in
the Smart
Contracts
Security
Course

Solidity
Smart
Contract
with
set
()
and
get
()
Functions

Another
notable
addition
among
the
top
Solidity
smart
contract
examples
is
the
smart
contract,
in
which
you
can
use
the
set
()
and
get
()
functions.
The
following
example
uses
the
set
()
function
to
set
the
value
of
the
state
variable
in
the
smart
contract.
On
the
other
hand,
the
get
()
function
can
help
in
obtaining
the
set
value
from
the
contract.

// SPDX-License-Identifier: GPL-3.0  pragma solidity >= 0.4.16 < 0.9.0; contract Storage {  uint public setData;  function set(uint x) public  {  setData = x;  }  function get(  ) public view returns (uint) {  return setData;  } }

Let
us
break
down
this
smart
contract
code
example
to
understand
how
you
can
also
create
a
contract
with
Solidity.
Here
are
the
important
components
that
you
must
note
in
the
contract
code
example.

• 
  Version
  Pragma

pragma solidity >=0.4.16 <0.9.0;

The
smart
contract
code
starts
with
pragmas,
which
serve
as
instructions
for
the
compiler
on
how
it
must
treat
the
code.
Every
Solidity
source
code
must
begin
with
the
‘version
pragma’
that
officially
declares
the
version
of
Solidity
compiler
it
would
use.
The
use
of
version
pragma
in
this
Solidity
contract
example
proves
its
functionality
in
any
Solidity
contract
code.
It
helps
prevent
any
compatibility
issues
with
the
future
versions
of
the
compiler
that
may
feature
some
changes.
In
this
example,
you
can
notice
that
the
code
is
compatible
with
compilers
with
a
version
more
than
0.4.16
and
less
than
0.9.0
version.

• 
  Contract
  Keyword

The
‘contract
Storage
{
}’
component
of
the
code
draws
attention
to
the
contract
keyword.
It
serves
a
valuable
role
in
declaring
a
contract
that
would
encapsulate
the
code. 

• 
  State
  Variables

Another
common
highlight
in
answers
to
“How
do
you
write
a
smart
contract
in
Solidity?”
draws
attention
to
state
variables.
In
this
example,
you
can
notice
state
variables
in
the
line,

uint
public
setData;

State
variables
are
permanent
additions
to
the
contract
storage
and
are
written
directly
to
the
Ethereum
blockchain.
The
concerned
line
in
the
code
example
provides
a
declaration
of
a
state
variable
“setData”
with
the
type
‘uint’
or
an
unsigned
integer
of
256
bits.
You
can
think
of
the
line
as
a
method
for
addition
of
slots
in
a
database. 

• 
  Function
  Declaration 

The
most
crucial
highlight
in
a
smart
contract
code
example
is
the
function
declaration,
which
looks
like
the
following,

function set(uint x) public function get() public view returns (uint)

You
can
notice
these
two
functions
at
distinct
parts
of
the
smart
contract
code.
First
of
all,
you
have
a
function
‘set,’
which
has
a
public
access
modifier
type.
The
function
would
take
variable
x
of
uint
data
type
as
the
parameter.
It
can
serve
as
an
essential
addition
to
a
simple,
smart
contract
for
updating
the
value
of
“setData.” 

The
function
allows
anyone
to
call
and
overwrite
the
value
of
“setData”
stored
in
Ethereum
blockchain
without
any
barriers.
Therefore,
you
would
have
a
completely

decentralized
and
censorship-resistant
smart
contract,
which
would
be
unaffected
by
centralized
server
shutdowns.

Are
you
aspiring
to
learn
the
fundamentals
of
the
Ethereum
Virtual
Machine
and
smart
contracts’
upgradability?
Enroll
now
in
the Advanced
Solidity
Development
Course.

What
are
the
Other
Solidity
Contract
Examples
You
Must
Learn?

The
simple
example
of
Solidity
contracts
showcases
the
fundamentals
you
need
to
find
your
way
through
Solidity
contract
development.
On
the
contrary,
you
can
seek
the
top
Solidity
smart
contract
examples
that
cater
to
emerging
requirements.
The
examples
can
not
only
help
you
understand
the
power
of
Solidity
but
also
help
you
level
up
your
game
in
Solidity
programming.
Here
are
some
of
the
notable
examples
of
Solidity
smart
contracts
for
different
purposes.

ERC-20
Token
Contract

ERC-20
token
standard
is
a
mandatory
addition
to
the
checklist
of
every
aspiring

Solidity
developer.
It
helps
in
defining
a
specific
set
of
rules
for
creation
of
fungible
tokens.
Here
is
an
example
of
an
ERC-20
token
contract
in
Solidity.

contract ERC20Token {
 string public name;
 string public symbol;
 uint8 public decimals = 18;
 uint256 public totalSupply;  mapping(address => uint256) public balanceOf;
 mapping(address => mapping(address => uint256)) public allowance;  event Transfer(address indexed from, address indexed to, uint256 value);
 event Approval(address indexed owner, address indexed spender, uint256 value);  constructor(uint256 initialSupply, string memory tokenName, string memory tokenSymbol) {
 totalSupply = initialSupply * 10 ** uint256(decimals);
 balanceOf[msg.sender] = totalSupply;
 name = tokenName;
 symbol = tokenSymbol;
 }  // Additional functions...
}

ERC-721
Token
Contract 

The
next
addition
among
best
Solidity
smart
contract
examples
would
draw
the
limelight
on

ERC-721
tokens.
You
can
use
ERC-721
standard
for
creating

NFTs.
Here
is
an
example
of
an
ERC-721
token
contract
on
Solidity.

contract ERC721Token {
 string public name;
 string public symbol;  mapping(uint256 => address) public ownerOf;
 mapping(address => uint256) public balance;
 mapping(uint256 => address) public approved;  event Transfer(address indexed from, address indexed to, uint256 tokenId);
 event Approval(address indexed owner, address indexed approved, uint256 tokenId);
 event ApprovalForAll(address indexed owner, address indexed operator, bool approved);  function transferFrom(address from, address to, uint256 tokenId) external;
 function approve(address to, uint256 tokenId) external;
 
 // Additional functions...
}

General
Auction
Contract

You
can
also
create
online
auctions
on
the
blockchain
with
Solidity
smart
contracts.
Developers
can
leverage
a
simple
auction
contract
for
this
purpose.
The
contract
can
help
bidders
compete
for
items,
and
the
highest
bidder
will
win
when
the
auction
ends.
Here
is
an
example
of
a
general
auction
contract
you
can
create
in
Solidity.

contract SimpleAuction {
 address public beneficiary;
 uint256 public auctionEndTime;  address public highestBidder;
 uint256 public highestBid;  mapping(address => uint256) public pendingReturns;  bool public ended;  event HighestBidIncreased(address bidder, uint256 amount);
 event AuctionEnded(address winner, uint256 amount);  constructor(uint256 _biddingTime, address _beneficiary) {
 beneficiary = _beneficiary;
 auctionEndTime = block.timestamp + _biddingTime;
 }  function bid() public payable;
 function withdraw() public returns (bool);
 function auctionEnd() public;
 
 // Additional functions...
}

Start
your
journey
to
become
a
smart
contract
developer
or
architect
with
an
in-depth
overview
of
smart
contract
fundamentals,
Enroll
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Contracts
Skill
Path

Final
Words

The
review
of
Solidity
smart
contract
examples
reveals
that
it
is
a
straightforward
and
simple
programming
language.
You
don’t
have
to
be
a
programming
expert
to
learn
how
Solidity
works.
On
top
of
it,
the
diverse
use
cases
of
Solidity
contracts
present
more
favorable
avenues
for
its
adoption.

Solidity
would
serve
as
a
major
force
in
the
web3
revolution
by
supporting
the

development
of
NFTs
and
dApps.
You
can
also
become
a
Solidity
expert
by
starting
your
learning
journey
as
soon
as
possible.
Learn
more
about
the

fundamentals
of
Solidity
and
how
you
can
extract
the
best
results
from
it
right
away.

*Disclaimer:
The
article
should
not
be
taken
as,
and
is
not
intended
to
provide
any
investment
advice.
Claims
made
in
this
article
do
not
constitute
investment
advice
and
should
not
be
taken
as
such.
101
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