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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)
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(int) + 4*5;
Why is this possible? (tried with g++ and gcc.)
c++ c casting language-lawyer
edited 9 mins ago
Davislor
9,10511227
asked 6 hours ago
Ernest BredarErnest Bredar
1005
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add a comment |
(int) + 4*5;
Why is this possible? (tried with g++ and gcc.)
c++ c casting language-lawyer
edited 9 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
3 hours ago
add a comment |
(int) + 4*5;
Why is this possible? (tried with g++ and gcc.)
c++ c casting language-lawyer
edited 9 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 9 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 9 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 9 mins ago
Davislor
9,10511227
edited 9 mins ago
Davislor
9,10511227
edited 9 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
3 hours ago
add a 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
3 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
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
3 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
3 hours ago
add a 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 |
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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.
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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
3 hours ago