Why do C and C++ allow the expression (int) + 4? Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 23, 2019 at 23:30 UTC (7:30pm US/Eastern) Data science time! April 2019 and salary with experience The Ask Question Wizard is Live!Cast int to enum in C#What are the differences between a pointer variable and a reference variable in C++?The Definitive C++ Book Guide and ListDo I cast the result of malloc?Why is “using namespace std” considered bad practice?What is the “-->” operator in C++?C++11 introduced a standardized memory model. What does it mean? And how is it going to affect C++ programming?Why are elementwise additions much faster in separate loops than in a combined loop?Why don't Java's +=, -=, *=, /= compound assignment operators require casting?Why is it faster to process a sorted array than an unsorted array?
New Order #6: Easter Egg
Should a wizard buy fine inks every time he want to copy spells into his spellbook?
Trying to understand entropy as a novice in thermodynamics
Can two people see the same photon?
Table formatting with tabularx?
What is the proper term for etching or digging of wall to hide conduit of cables
How to ask rejected full-time candidates to apply to teach individual courses?
Understanding piped command in Gnu/Linux
Can haste grant me and my beast master companion extra attacks?
What are some likely causes to domain member PC losing contact to domain controller?
Twin's vs. Twins'
My mentor says to set image to Fine instead of RAW — how is this different from JPG?
Did John Wesley plagiarize Matthew Henry...?
How to resize main filesystem
One-one communication
The bible of geometry: Is there a modern treatment of geometries from the most primitive to the most advanced?
Problem with display of presentation
Find general formula for the terms
Centre cell vertically in tabularx
Statistical analysis applied to methods coming out of Machine Learning
.bashrc alias for a command with fixed second parameter
Marquee sign letters
NIntegrate on a solution of a matrix ODE
Weaponising the Grasp-at-a-Distance spell
Why do C and C++ allow the expression (int) + 4?
Announcing the arrival of Valued Associate #679: Cesar Manara
Planned maintenance scheduled April 23, 2019 at 23:30 UTC (7:30pm US/Eastern)
Data science time! April 2019 and salary with experience
The Ask Question Wizard is Live!Cast int to enum in C#What are the differences between a pointer variable and a reference variable in C++?The Definitive C++ Book Guide and ListDo I cast the result of malloc?Why is “using namespace std” considered bad practice?What is the “-->” operator in C++?C++11 introduced a standardized memory model. What does it mean? And how is it going to affect C++ programming?Why are elementwise additions much faster in separate loops than in a combined loop?Why don't Java's +=, -=, *=, /= compound assignment operators require casting?Why is it faster to process a sorted array than an unsorted array?
.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty height:90px;width:728px;box-sizing:border-box;
(int) + 4*5;
Why is this possible? (tried with g++ and gcc.)
c++ c casting language-lawyer
edited 20 mins ago
Davislor
9,10511227
asked 6 hours ago
Ernest BredarErnest Bredar
1005
New contributor
Ernest Bredar is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
|
show 1 more comment
(int) + 4*5;
Why is this possible? (tried with g++ and gcc.)
c++ c casting language-lawyer
edited 20 mins ago
Davislor
9,10511227
asked 6 hours ago
Ernest BredarErnest Bredar
1005
New contributor
Ernest Bredar is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Even this is valid it is not a good idea to do that in a program because yes this is quite disturbing ^^
– bruno
6 hours ago
1
same as(int)-4*5
– P__J__
5 hours ago
Though "(int) (+4.0 * 5.0)" might make more sense, or "(double) (+4 * 5)". But this has me totally puzzled. Why would you write a line of code like this, without assigning the result, and why the heck does the compiler not at least issue a warning?/
– jamesqf
4 hours ago
1
@jamesqf I know that it dosn't make sense, but I want to know why this is possible and for this is sense not needed.
– Ernest Bredar
4 hours ago
1
There is a useful tool calledcppinsightsthat helps to understand how the code looks from the compiler frontend perspective. It also has an online version, you can see what it tells about your example (the same 'parenthesization' as the answers your were given)
– Nikita Kniazev
9 mins ago
|
show 1 more comment
(int) + 4*5;
Why is this possible? (tried with g++ and gcc.)
c++ c casting language-lawyer
edited 20 mins ago
Davislor
9,10511227
asked 6 hours ago
Ernest BredarErnest Bredar
1005
New contributor
Ernest Bredar is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
(int) + 4*5;
Why is this possible? (tried with g++ and gcc.)
c++ c casting language-lawyer
c++ c casting language-lawyer
edited 20 mins ago
Davislor
9,10511227
asked 6 hours ago
Ernest BredarErnest Bredar
1005
New contributor
Ernest Bredar is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 20 mins ago
Davislor
9,10511227
asked 6 hours ago
Ernest BredarErnest Bredar
1005
New contributor
Ernest Bredar is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 20 mins ago
Davislor
9,10511227
edited 20 mins ago
Davislor
9,10511227
edited 20 mins ago
Davislor
9,10511227
9,10511227
asked 6 hours ago
Ernest BredarErnest Bredar
1005
New contributor
Ernest Bredar is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 6 hours ago
Ernest BredarErnest Bredar
1005
asked 6 hours ago
Ernest BredarErnest Bredar
1005
1005
New contributor
Ernest Bredar is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Ernest Bredar is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Ernest Bredar is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Even this is valid it is not a good idea to do that in a program because yes this is quite disturbing ^^
– bruno
6 hours ago
1
same as(int)-4*5
– P__J__
5 hours ago
Though "(int) (+4.0 * 5.0)" might make more sense, or "(double) (+4 * 5)". But this has me totally puzzled. Why would you write a line of code like this, without assigning the result, and why the heck does the compiler not at least issue a warning?/
– jamesqf
4 hours ago
1
@jamesqf I know that it dosn't make sense, but I want to know why this is possible and for this is sense not needed.
– Ernest Bredar
4 hours ago
1
There is a useful tool calledcppinsightsthat helps to understand how the code looks from the compiler frontend perspective. It also has an online version, you can see what it tells about your example (the same 'parenthesization' as the answers your were given)
– Nikita Kniazev
9 mins ago
|
show 1 more comment
Even this is valid it is not a good idea to do that in a program because yes this is quite disturbing ^^
– bruno
6 hours ago
1
same as(int)-4*5
– P__J__
5 hours ago
Though "(int) (+4.0 * 5.0)" might make more sense, or "(double) (+4 * 5)". But this has me totally puzzled. Why would you write a line of code like this, without assigning the result, and why the heck does the compiler not at least issue a warning?/
– jamesqf
4 hours ago
1
@jamesqf I know that it dosn't make sense, but I want to know why this is possible and for this is sense not needed.
– Ernest Bredar
4 hours ago
1
There is a useful tool calledcppinsightsthat helps to understand how the code looks from the compiler frontend perspective. It also has an online version, you can see what it tells about your example (the same 'parenthesization' as the answers your were given)
– Nikita Kniazev
9 mins ago
Even this is valid it is not a good idea to do that in a program because yes this is quite disturbing ^^
– bruno
6 hours ago
Even this is valid it is not a good idea to do that in a program because yes this is quite disturbing ^^
– bruno
6 hours ago
1
1
same as
(int)-4*5– P__J__
5 hours ago
same as
(int)-4*5– P__J__
5 hours ago
Though "(int) (+4.0 * 5.0)" might make more sense, or "(double) (+4 * 5)". But this has me totally puzzled. Why would you write a line of code like this, without assigning the result, and why the heck does the compiler not at least issue a warning?/
– jamesqf
4 hours ago
Though "(int) (+4.0 * 5.0)" might make more sense, or "(double) (+4 * 5)". But this has me totally puzzled. Why would you write a line of code like this, without assigning the result, and why the heck does the compiler not at least issue a warning?/
– jamesqf
4 hours ago
1
1
@jamesqf I know that it dosn't make sense, but I want to know why this is possible and for this is sense not needed.
– Ernest Bredar
4 hours ago
@jamesqf I know that it dosn't make sense, but I want to know why this is possible and for this is sense not needed.
– Ernest Bredar
4 hours ago
1
1
There is a useful tool called
cppinsights that helps to understand how the code looks from the compiler frontend perspective. It also has an online version, you can see what it tells about your example (the same 'parenthesization' as the answers your were given)– Nikita Kniazev
9 mins ago
There is a useful tool called
cppinsights that helps to understand how the code looks from the compiler frontend perspective. It also has an online version, you can see what it tells about your example (the same 'parenthesization' as the answers your were given)– Nikita Kniazev
9 mins ago
|
show 1 more comment
2 Answers
2
active
oldest
votes
The + here is unary + operator, not the binary addition operator. There's no addition happening here.
Also, the syntax (int) is used for typecasting.
You can re-read that statement as
(int) (+ 4) * 5;
which is parsed as
((int) (+ 4)) * (5);
which says,
- Make the operand
+4 - typecasted to an
int - multiply with operand
5
This is similar to (int) (- 4) * (5);, where the usage of the unary operator is more familiar.
In your case, the unary + and the cast to int - both are redundant.
edited 3 hours ago
Dancrumb
18.2k448103
answered 6 hours ago
Sourav GhoshSourav Ghosh
112k15136194
add a comment |
This is interpreted as ((int)(+4)) * 5. That is, an expression +4 (a unary plus operator applied to a literal 4), cast to type int with a C-style cast, and the result multiplied by 5.
answered 6 hours ago
Igor TandetnikIgor Tandetnik
33.4k33559
add a comment |
Your Answer
StackExchange.ifUsing("editor", function ()
StackExchange.using("externalEditor", function ()
StackExchange.using("snippets", function ()
StackExchange.snippets.init();
);
);
, "code-snippets");
StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "1"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);
else
createEditor();
);
function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);
);
Ernest Bredar is a new contributor. Be nice, and check out our Code of Conduct.
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f55783615%2fwhy-do-c-and-c-allow-the-expression-int-4%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
The + here is unary + operator, not the binary addition operator. There's no addition happening here.
Also, the syntax (int) is used for typecasting.
You can re-read that statement as
(int) (+ 4) * 5;
which is parsed as
((int) (+ 4)) * (5);
which says,
- Make the operand
+4 - typecasted to an
int - multiply with operand
5
This is similar to (int) (- 4) * (5);, where the usage of the unary operator is more familiar.
In your case, the unary + and the cast to int - both are redundant.
edited 3 hours ago
Dancrumb
18.2k448103
answered 6 hours ago
Sourav GhoshSourav Ghosh
112k15136194
add a comment |
The + here is unary + operator, not the binary addition operator. There's no addition happening here.
Also, the syntax (int) is used for typecasting.
You can re-read that statement as
(int) (+ 4) * 5;
which is parsed as
((int) (+ 4)) * (5);
which says,
- Make the operand
+4 - typecasted to an
int - multiply with operand
5
This is similar to (int) (- 4) * (5);, where the usage of the unary operator is more familiar.
In your case, the unary + and the cast to int - both are redundant.
edited 3 hours ago
Dancrumb
18.2k448103
answered 6 hours ago
Sourav GhoshSourav Ghosh
112k15136194
add a comment |
The + here is unary + operator, not the binary addition operator. There's no addition happening here.
Also, the syntax (int) is used for typecasting.
You can re-read that statement as
(int) (+ 4) * 5;
which is parsed as
((int) (+ 4)) * (5);
which says,
- Make the operand
+4 - typecasted to an
int - multiply with operand
5
This is similar to (int) (- 4) * (5);, where the usage of the unary operator is more familiar.
In your case, the unary + and the cast to int - both are redundant.
edited 3 hours ago
Dancrumb
18.2k448103
answered 6 hours ago
Sourav GhoshSourav Ghosh
112k15136194
The + here is unary + operator, not the binary addition operator. There's no addition happening here.
Also, the syntax (int) is used for typecasting.
You can re-read that statement as
(int) (+ 4) * 5;
which is parsed as
((int) (+ 4)) * (5);
which says,
- Make the operand
+4 - typecasted to an
int - multiply with operand
5
This is similar to (int) (- 4) * (5);, where the usage of the unary operator is more familiar.
In your case, the unary + and the cast to int - both are redundant.
edited 3 hours ago
Dancrumb
18.2k448103
answered 6 hours ago
Sourav GhoshSourav Ghosh
112k15136194
edited 3 hours ago
Dancrumb
18.2k448103
edited 3 hours ago
Dancrumb
18.2k448103
edited 3 hours ago
Dancrumb
18.2k448103
18.2k448103
answered 6 hours ago
Sourav GhoshSourav Ghosh
112k15136194
answered 6 hours ago
Sourav GhoshSourav Ghosh
112k15136194
answered 6 hours ago
Sourav GhoshSourav Ghosh
112k15136194
112k15136194
add a comment |
add a comment |
This is interpreted as ((int)(+4)) * 5. That is, an expression +4 (a unary plus operator applied to a literal 4), cast to type int with a C-style cast, and the result multiplied by 5.
answered 6 hours ago
Igor TandetnikIgor Tandetnik
33.4k33559
add a comment |
This is interpreted as ((int)(+4)) * 5. That is, an expression +4 (a unary plus operator applied to a literal 4), cast to type int with a C-style cast, and the result multiplied by 5.
answered 6 hours ago
Igor TandetnikIgor Tandetnik
33.4k33559
add a comment |
This is interpreted as ((int)(+4)) * 5. That is, an expression +4 (a unary plus operator applied to a literal 4), cast to type int with a C-style cast, and the result multiplied by 5.
answered 6 hours ago
Igor TandetnikIgor Tandetnik
33.4k33559
This is interpreted as ((int)(+4)) * 5. That is, an expression +4 (a unary plus operator applied to a literal 4), cast to type int with a C-style cast, and the result multiplied by 5.
answered 6 hours ago
Igor TandetnikIgor Tandetnik
33.4k33559
answered 6 hours ago
Igor TandetnikIgor Tandetnik
33.4k33559
answered 6 hours ago
Igor TandetnikIgor Tandetnik
33.4k33559
answered 6 hours ago
Igor TandetnikIgor Tandetnik
33.4k33559
33.4k33559
add a comment |
add a comment |
Ernest Bredar is a new contributor. Be nice, and check out our Code of Conduct.
Ernest Bredar is a new contributor. Be nice, and check out our Code of Conduct.
Ernest Bredar is a new contributor. Be nice, and check out our Code of Conduct.
Ernest Bredar is a new contributor. Be nice, and check out our Code of Conduct.
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f55783615%2fwhy-do-c-and-c-allow-the-expression-int-4%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Even this is valid it is not a good idea to do that in a program because yes this is quite disturbing ^^
– bruno
6 hours ago
1
same as
(int)-4*5– P__J__
5 hours ago
Though "(int) (+4.0 * 5.0)" might make more sense, or "(double) (+4 * 5)". But this has me totally puzzled. Why would you write a line of code like this, without assigning the result, and why the heck does the compiler not at least issue a warning?/
– jamesqf
4 hours ago
1
@jamesqf I know that it dosn't make sense, but I want to know why this is possible and for this is sense not needed.
– Ernest Bredar
4 hours ago
1
There is a useful tool called
cppinsightsthat helps to understand how the code looks from the compiler frontend perspective. It also has an online version, you can see what it tells about your example (the same 'parenthesization' as the answers your were given)– Nikita Kniazev
9 mins ago