What does ? in C mean?
What does a question mark (?) in C mean?
c
asked Feb 3 '11 at 10:43
Eric Brotto
35.7k26108168
|
show 1 more comment
What does a question mark (?) in C mean?
c
asked Feb 3 '11 at 10:43
Eric Brotto
35.7k26108168
1
Could you give us a contextual example of where you're seeing the '?'?
– Rich Turner
Feb 3 '11 at 10:45
@bitcrazed: Just curious: what other use than the ternary operator are you thinking of?
– chris
Feb 3 '11 at 10:48
@chris it's also (in seriously old code) part of a trigraph, as Benoit beat me to answering.
– Rup
Feb 3 '11 at 10:50
@bitcrazed: I read about those, never seen them in actual code though. Not even in really old code ;)
– chris
Feb 3 '11 at 10:58
1
@chris You're more likely to accidentally enter one and get compiler warnings about them rather than find real examples, yes.
– Rup
Feb 3 '11 at 10:59
|
show 1 more comment
What does a question mark (?) in C mean?
c
asked Feb 3 '11 at 10:43
Eric Brotto
35.7k26108168
What does a question mark (?) in C mean?
c
c
asked Feb 3 '11 at 10:43
Eric Brotto
35.7k26108168
asked Feb 3 '11 at 10:43
Eric Brotto
35.7k26108168
asked Feb 3 '11 at 10:43
Eric Brotto
35.7k26108168
asked Feb 3 '11 at 10:43
Eric Brotto
35.7k26108168
asked Feb 3 '11 at 10:43
Eric Brotto
35.7k26108168
35.7k26108168
1
Could you give us a contextual example of where you're seeing the '?'?
– Rich Turner
Feb 3 '11 at 10:45
@bitcrazed: Just curious: what other use than the ternary operator are you thinking of?
– chris
Feb 3 '11 at 10:48
@chris it's also (in seriously old code) part of a trigraph, as Benoit beat me to answering.
– Rup
Feb 3 '11 at 10:50
@bitcrazed: I read about those, never seen them in actual code though. Not even in really old code ;)
– chris
Feb 3 '11 at 10:58
1
@chris You're more likely to accidentally enter one and get compiler warnings about them rather than find real examples, yes.
– Rup
Feb 3 '11 at 10:59
|
show 1 more comment
1
Could you give us a contextual example of where you're seeing the '?'?
– Rich Turner
Feb 3 '11 at 10:45
@bitcrazed: Just curious: what other use than the ternary operator are you thinking of?
– chris
Feb 3 '11 at 10:48
@chris it's also (in seriously old code) part of a trigraph, as Benoit beat me to answering.
– Rup
Feb 3 '11 at 10:50
@bitcrazed: I read about those, never seen them in actual code though. Not even in really old code ;)
– chris
Feb 3 '11 at 10:58
1
@chris You're more likely to accidentally enter one and get compiler warnings about them rather than find real examples, yes.
– Rup
Feb 3 '11 at 10:59
1
1
Could you give us a contextual example of where you're seeing the '?'?
– Rich Turner
Feb 3 '11 at 10:45
Could you give us a contextual example of where you're seeing the '?'?
– Rich Turner
Feb 3 '11 at 10:45
@bitcrazed: Just curious: what other use than the ternary operator are you thinking of?
– chris
Feb 3 '11 at 10:48
@bitcrazed: Just curious: what other use than the ternary operator are you thinking of?
– chris
Feb 3 '11 at 10:48
@chris it's also (in seriously old code) part of a trigraph, as Benoit beat me to answering.
– Rup
Feb 3 '11 at 10:50
@chris it's also (in seriously old code) part of a trigraph, as Benoit beat me to answering.
– Rup
Feb 3 '11 at 10:50
@bitcrazed: I read about those, never seen them in actual code though. Not even in really old code ;)
– chris
Feb 3 '11 at 10:58
@bitcrazed: I read about those, never seen them in actual code though. Not even in really old code ;)
– chris
Feb 3 '11 at 10:58
1
1
@chris You're more likely to accidentally enter one and get compiler warnings about them rather than find real examples, yes.
– Rup
Feb 3 '11 at 10:59
@chris You're more likely to accidentally enter one and get compiler warnings about them rather than find real examples, yes.
– Rup
Feb 3 '11 at 10:59
|
show 1 more comment
8 Answers
8
active
oldest
votes
? is the first symbol of the ?: ternary operator.
a = (b==0) ? 1 : 0;
a will have the value 1 if b is equal to 0, and 0 otherwise.
answered Feb 3 '11 at 10:45
Didier Trosset
27k1263100
add a comment |
Additionally to other answers, ? can be part of a trigraph.
edited Mar 24 '16 at 14:55
tripleee
88.6k12124179
answered Feb 3 '11 at 10:47
Benoit
58.8k15164212
It can also be part of a string or character in general without being a trigraph:char c = '?'; char const * s = "?".
– Thomas Eding
Dec 8 '11 at 22:33
add a comment |
This is a ternary Operator which is conditional operator uses like if-else
example
int i=1;
int j=2;
int k;
k= i > j ? i : j;
//which is same as
if(i>j)
k=i;
else
k=j;
Usage:
Syntax of ?: is
assignment_Variable = Condition ? value_if_true : value_if_false;
answered Feb 3 '11 at 10:48
Javed Akram
9,6032170109
add a comment |
That’s probably a part of the ternary operator:
const int numApples = …;
printf("I have %i apple%s.n", numApples == 1 ? "" : "s");
answered Feb 3 '11 at 10:45
zoul
77.9k36218322
Just to save future generations on any confusion here. It is the "conditional operator". It just happens to be a ternary operator, of which there is only one in C and C++. There are lots of unary (~, !, -) and binary (+, -, <<) operators in C/C++ as well. Neato!
– Thomas Eding
Dec 8 '11 at 22:17
add a comment |
This is a so called conditional operator. You can shorten your if else statement with this operator.
The following link should explain everything
http://www.crasseux.com/books/ctutorial/The-question-mark-operator.html
answered Feb 3 '11 at 10:46
Stefan Papp
1,27311334
add a comment |
It is a conditional operator. For example refer the below link
http://en.wikipedia.org/wiki/Conditional_operator
answered Feb 3 '11 at 10:45
ckv
5,1361562121
add a comment |
Its the ternary operator, see http://en.wikipedia.org/wiki/Ternary_operation#C.2C_C.2B.2B.2C_C.23.2C_Objective-C.2C_Java.2C_JavaScript.2C_ActionScript
answered Feb 3 '11 at 10:45
ismail
33.9k86886
add a comment |
Most likely the '?' is the ternary operator. Its grammar is:
RESULT = (COND) ? (STATEMEN IF TRUE) : (STATEMENT IF FALSE)
It is a nice shorthand for the typical if-else statement:
if (COND) {
RESULT = (STATEMENT IF TRUE);
} else {
RESULT = (STATEMENT IF FALSE);
as it can usually fit on one line and can improve readability.
Some answers here refer to a trigraph, which is relevant to the C preprocessor. Take a look at this really dumb program, trigraphs.c:
# /* preprocessor will remove single hash symbols and this comment */
int main()
{
char *t = "??=";
char *p = "??/"";
char *s = "??'";
??(, ??), ??! ??<, ??>, ??-
return 0;
}
invoking only the c preprocessor by running gcc -E -trigraphs trigraph.c the output is
int main()
{
char *t = "#"
char *p = """;
char *s = "^";
[, ], | {, }, ~
return 0;
}
Hopefully that clarifies a little bit what a trigraphs are, and what a '?' "means" in C.
answered Jan 23 '16 at 19:41
bpm
874
add a comment |
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8 Answers
8
active
oldest
votes
8 Answers
8
active
oldest
votes
active
oldest
votes
active
oldest
votes
? is the first symbol of the ?: ternary operator.
a = (b==0) ? 1 : 0;
a will have the value 1 if b is equal to 0, and 0 otherwise.
answered Feb 3 '11 at 10:45
Didier Trosset
27k1263100
add a comment |
? is the first symbol of the ?: ternary operator.
a = (b==0) ? 1 : 0;
a will have the value 1 if b is equal to 0, and 0 otherwise.
answered Feb 3 '11 at 10:45
Didier Trosset
27k1263100
add a comment |
? is the first symbol of the ?: ternary operator.
a = (b==0) ? 1 : 0;
a will have the value 1 if b is equal to 0, and 0 otherwise.
answered Feb 3 '11 at 10:45
Didier Trosset
27k1263100
? is the first symbol of the ?: ternary operator.
a = (b==0) ? 1 : 0;
a will have the value 1 if b is equal to 0, and 0 otherwise.
answered Feb 3 '11 at 10:45
Didier Trosset
27k1263100
answered Feb 3 '11 at 10:45
Didier Trosset
27k1263100
answered Feb 3 '11 at 10:45
Didier Trosset
27k1263100
answered Feb 3 '11 at 10:45
Didier Trosset
27k1263100
27k1263100
add a comment |
add a comment |
Additionally to other answers, ? can be part of a trigraph.
edited Mar 24 '16 at 14:55
tripleee
88.6k12124179
answered Feb 3 '11 at 10:47
Benoit
58.8k15164212
It can also be part of a string or character in general without being a trigraph:char c = '?'; char const * s = "?".
– Thomas Eding
Dec 8 '11 at 22:33
add a comment |
Additionally to other answers, ? can be part of a trigraph.
edited Mar 24 '16 at 14:55
tripleee
88.6k12124179
answered Feb 3 '11 at 10:47
Benoit
58.8k15164212
It can also be part of a string or character in general without being a trigraph:char c = '?'; char const * s = "?".
– Thomas Eding
Dec 8 '11 at 22:33
add a comment |
Additionally to other answers, ? can be part of a trigraph.
edited Mar 24 '16 at 14:55
tripleee
88.6k12124179
answered Feb 3 '11 at 10:47
Benoit
58.8k15164212
Additionally to other answers, ? can be part of a trigraph.
edited Mar 24 '16 at 14:55
tripleee
88.6k12124179
answered Feb 3 '11 at 10:47
Benoit
58.8k15164212
edited Mar 24 '16 at 14:55
tripleee
88.6k12124179
edited Mar 24 '16 at 14:55
tripleee
88.6k12124179
edited Mar 24 '16 at 14:55
tripleee
88.6k12124179
88.6k12124179
answered Feb 3 '11 at 10:47
Benoit
58.8k15164212
answered Feb 3 '11 at 10:47
Benoit
58.8k15164212
answered Feb 3 '11 at 10:47
Benoit
58.8k15164212
58.8k15164212
It can also be part of a string or character in general without being a trigraph:char c = '?'; char const * s = "?".
– Thomas Eding
Dec 8 '11 at 22:33
add a comment |
It can also be part of a string or character in general without being a trigraph:char c = '?'; char const * s = "?".
– Thomas Eding
Dec 8 '11 at 22:33
It can also be part of a string or character in general without being a trigraph:
char c = '?'; char const * s = "?".– Thomas Eding
Dec 8 '11 at 22:33
It can also be part of a string or character in general without being a trigraph:
char c = '?'; char const * s = "?".– Thomas Eding
Dec 8 '11 at 22:33
add a comment |
This is a ternary Operator which is conditional operator uses like if-else
example
int i=1;
int j=2;
int k;
k= i > j ? i : j;
//which is same as
if(i>j)
k=i;
else
k=j;
Usage:
Syntax of ?: is
assignment_Variable = Condition ? value_if_true : value_if_false;
answered Feb 3 '11 at 10:48
Javed Akram
9,6032170109
add a comment |
This is a ternary Operator which is conditional operator uses like if-else
example
int i=1;
int j=2;
int k;
k= i > j ? i : j;
//which is same as
if(i>j)
k=i;
else
k=j;
Usage:
Syntax of ?: is
assignment_Variable = Condition ? value_if_true : value_if_false;
answered Feb 3 '11 at 10:48
Javed Akram
9,6032170109
add a comment |
This is a ternary Operator which is conditional operator uses like if-else
example
int i=1;
int j=2;
int k;
k= i > j ? i : j;
//which is same as
if(i>j)
k=i;
else
k=j;
Usage:
Syntax of ?: is
assignment_Variable = Condition ? value_if_true : value_if_false;
answered Feb 3 '11 at 10:48
Javed Akram
9,6032170109
This is a ternary Operator which is conditional operator uses like if-else
example
int i=1;
int j=2;
int k;
k= i > j ? i : j;
//which is same as
if(i>j)
k=i;
else
k=j;
Usage:
Syntax of ?: is
assignment_Variable = Condition ? value_if_true : value_if_false;
answered Feb 3 '11 at 10:48
Javed Akram
9,6032170109
edited Feb 3 '11 at 10:54
answered Feb 3 '11 at 10:48
Javed Akram
9,6032170109
answered Feb 3 '11 at 10:48
Javed Akram
9,6032170109
answered Feb 3 '11 at 10:48
Javed Akram
9,6032170109
9,6032170109
add a comment |
add a comment |
That’s probably a part of the ternary operator:
const int numApples = …;
printf("I have %i apple%s.n", numApples == 1 ? "" : "s");
answered Feb 3 '11 at 10:45
zoul
77.9k36218322
Just to save future generations on any confusion here. It is the "conditional operator". It just happens to be a ternary operator, of which there is only one in C and C++. There are lots of unary (~, !, -) and binary (+, -, <<) operators in C/C++ as well. Neato!
– Thomas Eding
Dec 8 '11 at 22:17
add a comment |
That’s probably a part of the ternary operator:
const int numApples = …;
printf("I have %i apple%s.n", numApples == 1 ? "" : "s");
answered Feb 3 '11 at 10:45
zoul
77.9k36218322
Just to save future generations on any confusion here. It is the "conditional operator". It just happens to be a ternary operator, of which there is only one in C and C++. There are lots of unary (~, !, -) and binary (+, -, <<) operators in C/C++ as well. Neato!
– Thomas Eding
Dec 8 '11 at 22:17
add a comment |
That’s probably a part of the ternary operator:
const int numApples = …;
printf("I have %i apple%s.n", numApples == 1 ? "" : "s");
answered Feb 3 '11 at 10:45
zoul
77.9k36218322
That’s probably a part of the ternary operator:
const int numApples = …;
printf("I have %i apple%s.n", numApples == 1 ? "" : "s");
answered Feb 3 '11 at 10:45
zoul
77.9k36218322
answered Feb 3 '11 at 10:45
zoul
77.9k36218322
answered Feb 3 '11 at 10:45
zoul
77.9k36218322
answered Feb 3 '11 at 10:45
zoul
77.9k36218322
77.9k36218322
Just to save future generations on any confusion here. It is the "conditional operator". It just happens to be a ternary operator, of which there is only one in C and C++. There are lots of unary (~, !, -) and binary (+, -, <<) operators in C/C++ as well. Neato!
– Thomas Eding
Dec 8 '11 at 22:17
add a comment |
Just to save future generations on any confusion here. It is the "conditional operator". It just happens to be a ternary operator, of which there is only one in C and C++. There are lots of unary (~, !, -) and binary (+, -, <<) operators in C/C++ as well. Neato!
– Thomas Eding
Dec 8 '11 at 22:17
Just to save future generations on any confusion here. It is the "conditional operator". It just happens to be a ternary operator, of which there is only one in C and C++. There are lots of unary (~, !, -) and binary (+, -, <<) operators in C/C++ as well. Neato!
– Thomas Eding
Dec 8 '11 at 22:17
Just to save future generations on any confusion here. It is the "conditional operator". It just happens to be a ternary operator, of which there is only one in C and C++. There are lots of unary (~, !, -) and binary (+, -, <<) operators in C/C++ as well. Neato!
– Thomas Eding
Dec 8 '11 at 22:17
add a comment |
This is a so called conditional operator. You can shorten your if else statement with this operator.
The following link should explain everything
http://www.crasseux.com/books/ctutorial/The-question-mark-operator.html
answered Feb 3 '11 at 10:46
Stefan Papp
1,27311334
add a comment |
This is a so called conditional operator. You can shorten your if else statement with this operator.
The following link should explain everything
http://www.crasseux.com/books/ctutorial/The-question-mark-operator.html
answered Feb 3 '11 at 10:46
Stefan Papp
1,27311334
add a comment |
This is a so called conditional operator. You can shorten your if else statement with this operator.
The following link should explain everything
http://www.crasseux.com/books/ctutorial/The-question-mark-operator.html
answered Feb 3 '11 at 10:46
Stefan Papp
1,27311334
This is a so called conditional operator. You can shorten your if else statement with this operator.
The following link should explain everything
http://www.crasseux.com/books/ctutorial/The-question-mark-operator.html
answered Feb 3 '11 at 10:46
Stefan Papp
1,27311334
answered Feb 3 '11 at 10:46
Stefan Papp
1,27311334
answered Feb 3 '11 at 10:46
Stefan Papp
1,27311334
answered Feb 3 '11 at 10:46
Stefan Papp
1,27311334
1,27311334
add a comment |
add a comment |
It is a conditional operator. For example refer the below link
http://en.wikipedia.org/wiki/Conditional_operator
answered Feb 3 '11 at 10:45
ckv
5,1361562121
add a comment |
It is a conditional operator. For example refer the below link
http://en.wikipedia.org/wiki/Conditional_operator
answered Feb 3 '11 at 10:45
ckv
5,1361562121
add a comment |
It is a conditional operator. For example refer the below link
http://en.wikipedia.org/wiki/Conditional_operator
answered Feb 3 '11 at 10:45
ckv
5,1361562121
It is a conditional operator. For example refer the below link
http://en.wikipedia.org/wiki/Conditional_operator
answered Feb 3 '11 at 10:45
ckv
5,1361562121
answered Feb 3 '11 at 10:45
ckv
5,1361562121
answered Feb 3 '11 at 10:45
ckv
5,1361562121
answered Feb 3 '11 at 10:45
ckv
5,1361562121
5,1361562121
add a comment |
add a comment |
Its the ternary operator, see http://en.wikipedia.org/wiki/Ternary_operation#C.2C_C.2B.2B.2C_C.23.2C_Objective-C.2C_Java.2C_JavaScript.2C_ActionScript
answered Feb 3 '11 at 10:45
ismail
33.9k86886
add a comment |
Its the ternary operator, see http://en.wikipedia.org/wiki/Ternary_operation#C.2C_C.2B.2B.2C_C.23.2C_Objective-C.2C_Java.2C_JavaScript.2C_ActionScript
answered Feb 3 '11 at 10:45
ismail
33.9k86886
add a comment |
Its the ternary operator, see http://en.wikipedia.org/wiki/Ternary_operation#C.2C_C.2B.2B.2C_C.23.2C_Objective-C.2C_Java.2C_JavaScript.2C_ActionScript
answered Feb 3 '11 at 10:45
ismail
33.9k86886
Its the ternary operator, see http://en.wikipedia.org/wiki/Ternary_operation#C.2C_C.2B.2B.2C_C.23.2C_Objective-C.2C_Java.2C_JavaScript.2C_ActionScript
answered Feb 3 '11 at 10:45
ismail
33.9k86886
answered Feb 3 '11 at 10:45
ismail
33.9k86886
answered Feb 3 '11 at 10:45
ismail
33.9k86886
answered Feb 3 '11 at 10:45
ismail
33.9k86886
33.9k86886
add a comment |
add a comment |
Most likely the '?' is the ternary operator. Its grammar is:
RESULT = (COND) ? (STATEMEN IF TRUE) : (STATEMENT IF FALSE)
It is a nice shorthand for the typical if-else statement:
if (COND) {
RESULT = (STATEMENT IF TRUE);
} else {
RESULT = (STATEMENT IF FALSE);
as it can usually fit on one line and can improve readability.
Some answers here refer to a trigraph, which is relevant to the C preprocessor. Take a look at this really dumb program, trigraphs.c:
# /* preprocessor will remove single hash symbols and this comment */
int main()
{
char *t = "??=";
char *p = "??/"";
char *s = "??'";
??(, ??), ??! ??<, ??>, ??-
return 0;
}
invoking only the c preprocessor by running gcc -E -trigraphs trigraph.c the output is
int main()
{
char *t = "#"
char *p = """;
char *s = "^";
[, ], | {, }, ~
return 0;
}
Hopefully that clarifies a little bit what a trigraphs are, and what a '?' "means" in C.
answered Jan 23 '16 at 19:41
bpm
874
add a comment |
Most likely the '?' is the ternary operator. Its grammar is:
RESULT = (COND) ? (STATEMEN IF TRUE) : (STATEMENT IF FALSE)
It is a nice shorthand for the typical if-else statement:
if (COND) {
RESULT = (STATEMENT IF TRUE);
} else {
RESULT = (STATEMENT IF FALSE);
as it can usually fit on one line and can improve readability.
Some answers here refer to a trigraph, which is relevant to the C preprocessor. Take a look at this really dumb program, trigraphs.c:
# /* preprocessor will remove single hash symbols and this comment */
int main()
{
char *t = "??=";
char *p = "??/"";
char *s = "??'";
??(, ??), ??! ??<, ??>, ??-
return 0;
}
invoking only the c preprocessor by running gcc -E -trigraphs trigraph.c the output is
int main()
{
char *t = "#"
char *p = """;
char *s = "^";
[, ], | {, }, ~
return 0;
}
Hopefully that clarifies a little bit what a trigraphs are, and what a '?' "means" in C.
answered Jan 23 '16 at 19:41
bpm
874
add a comment |
Most likely the '?' is the ternary operator. Its grammar is:
RESULT = (COND) ? (STATEMEN IF TRUE) : (STATEMENT IF FALSE)
It is a nice shorthand for the typical if-else statement:
if (COND) {
RESULT = (STATEMENT IF TRUE);
} else {
RESULT = (STATEMENT IF FALSE);
as it can usually fit on one line and can improve readability.
Some answers here refer to a trigraph, which is relevant to the C preprocessor. Take a look at this really dumb program, trigraphs.c:
# /* preprocessor will remove single hash symbols and this comment */
int main()
{
char *t = "??=";
char *p = "??/"";
char *s = "??'";
??(, ??), ??! ??<, ??>, ??-
return 0;
}
invoking only the c preprocessor by running gcc -E -trigraphs trigraph.c the output is
int main()
{
char *t = "#"
char *p = """;
char *s = "^";
[, ], | {, }, ~
return 0;
}
Hopefully that clarifies a little bit what a trigraphs are, and what a '?' "means" in C.
answered Jan 23 '16 at 19:41
bpm
874
Most likely the '?' is the ternary operator. Its grammar is:
RESULT = (COND) ? (STATEMEN IF TRUE) : (STATEMENT IF FALSE)
It is a nice shorthand for the typical if-else statement:
if (COND) {
RESULT = (STATEMENT IF TRUE);
} else {
RESULT = (STATEMENT IF FALSE);
as it can usually fit on one line and can improve readability.
Some answers here refer to a trigraph, which is relevant to the C preprocessor. Take a look at this really dumb program, trigraphs.c:
# /* preprocessor will remove single hash symbols and this comment */
int main()
{
char *t = "??=";
char *p = "??/"";
char *s = "??'";
??(, ??), ??! ??<, ??>, ??-
return 0;
}
invoking only the c preprocessor by running gcc -E -trigraphs trigraph.c the output is
int main()
{
char *t = "#"
char *p = """;
char *s = "^";
[, ], | {, }, ~
return 0;
}
Hopefully that clarifies a little bit what a trigraphs are, and what a '?' "means" in C.
answered Jan 23 '16 at 19:41
bpm
874
answered Jan 23 '16 at 19:41
bpm
874
answered Jan 23 '16 at 19:41
bpm
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answered Jan 23 '16 at 19:41
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1
Could you give us a contextual example of where you're seeing the '?'?
– Rich Turner
Feb 3 '11 at 10:45
@bitcrazed: Just curious: what other use than the ternary operator are you thinking of?
– chris
Feb 3 '11 at 10:48
@chris it's also (in seriously old code) part of a trigraph, as Benoit beat me to answering.
– Rup
Feb 3 '11 at 10:50
@bitcrazed: I read about those, never seen them in actual code though. Not even in really old code ;)
– chris
Feb 3 '11 at 10:58
1
@chris You're more likely to accidentally enter one and get compiler warnings about them rather than find real examples, yes.
– Rup
Feb 3 '11 at 10:59