While loop - how to remove code duplication
It's not the first time I find myself in the following situation:
bool a = some_very_long_computation;
bool b = another_very_long_computation;
while (a && b) {
...
a = some_very_long_computation;
b = another_very_long_computation;
}
I don't want to compute everything in while condition, since computations are long and I want to give them appropriate names.
I don't want to create helper functions, because computation uses many local variables, and passing them all will make the code much less readable (and it will be some_huge_call).
It's unknown whether loop body will be executed at least once.
What is a good pattern in such situation? Currently I face it in C++, but I've encountered this in other languages as well. I can solve it by using additional variable isFirstPass, but it looks ugly (and, I guess, will cause some warnings):
bool a, b;
bool isFirstPass = true;
do {
if (!isFirstPass) {
...
} else {
isFirstPass = false;
}
a = some_very_long_computation;
b = another_very_long_computation;
} while (a && b);
c++ duplicates code-duplication
edited Jan 19 at 0:39
melpomene
59.6k54692
asked Jan 18 at 18:55
dyukhadyukha
507310
|
show 1 more comment
It's not the first time I find myself in the following situation:
bool a = some_very_long_computation;
bool b = another_very_long_computation;
while (a && b) {
...
a = some_very_long_computation;
b = another_very_long_computation;
}
I don't want to compute everything in while condition, since computations are long and I want to give them appropriate names.
I don't want to create helper functions, because computation uses many local variables, and passing them all will make the code much less readable (and it will be some_huge_call).
It's unknown whether loop body will be executed at least once.
What is a good pattern in such situation? Currently I face it in C++, but I've encountered this in other languages as well. I can solve it by using additional variable isFirstPass, but it looks ugly (and, I guess, will cause some warnings):
bool a, b;
bool isFirstPass = true;
do {
if (!isFirstPass) {
...
} else {
isFirstPass = false;
}
a = some_very_long_computation;
b = another_very_long_computation;
} while (a && b);
c++ duplicates code-duplication
edited Jan 19 at 0:39
melpomene
59.6k54692
asked Jan 18 at 18:55
dyukhadyukha
507310
1
I do believe helper functions are still the right way to do; but what about macros?
– raina77ow
Jan 18 at 18:57
1
Macros - absolutely no. I don't want to pollute defines for some local stuff (and I can accidentally override some defines).
– dyukha
Jan 18 at 18:59
Meh, move it into its own method returning a bool.
– Will
Jan 18 at 18:59
Please update your first example making it clear how/if the first pass is different
– Lyndon White
Jan 19 at 0:24
@LyndonWhite, Sorry, I don't understand you. It's not different, it's the same pass as the others.
– dyukha
Jan 19 at 0:25
|
show 1 more comment
It's not the first time I find myself in the following situation:
bool a = some_very_long_computation;
bool b = another_very_long_computation;
while (a && b) {
...
a = some_very_long_computation;
b = another_very_long_computation;
}
I don't want to compute everything in while condition, since computations are long and I want to give them appropriate names.
I don't want to create helper functions, because computation uses many local variables, and passing them all will make the code much less readable (and it will be some_huge_call).
It's unknown whether loop body will be executed at least once.
What is a good pattern in such situation? Currently I face it in C++, but I've encountered this in other languages as well. I can solve it by using additional variable isFirstPass, but it looks ugly (and, I guess, will cause some warnings):
bool a, b;
bool isFirstPass = true;
do {
if (!isFirstPass) {
...
} else {
isFirstPass = false;
}
a = some_very_long_computation;
b = another_very_long_computation;
} while (a && b);
c++ duplicates code-duplication
edited Jan 19 at 0:39
melpomene
59.6k54692
asked Jan 18 at 18:55
dyukhadyukha
507310
It's not the first time I find myself in the following situation:
bool a = some_very_long_computation;
bool b = another_very_long_computation;
while (a && b) {
...
a = some_very_long_computation;
b = another_very_long_computation;
}
I don't want to compute everything in while condition, since computations are long and I want to give them appropriate names.
I don't want to create helper functions, because computation uses many local variables, and passing them all will make the code much less readable (and it will be some_huge_call).
It's unknown whether loop body will be executed at least once.
What is a good pattern in such situation? Currently I face it in C++, but I've encountered this in other languages as well. I can solve it by using additional variable isFirstPass, but it looks ugly (and, I guess, will cause some warnings):
bool a, b;
bool isFirstPass = true;
do {
if (!isFirstPass) {
...
} else {
isFirstPass = false;
}
a = some_very_long_computation;
b = another_very_long_computation;
} while (a && b);
c++ duplicates code-duplication
c++ duplicates code-duplication
edited Jan 19 at 0:39
melpomene
59.6k54692
asked Jan 18 at 18:55
dyukhadyukha
507310
edited Jan 19 at 0:39
melpomene
59.6k54692
asked Jan 18 at 18:55
dyukhadyukha
507310
edited Jan 19 at 0:39
melpomene
59.6k54692
edited Jan 19 at 0:39
melpomene
59.6k54692
edited Jan 19 at 0:39
melpomene
59.6k54692
59.6k54692
asked Jan 18 at 18:55
dyukhadyukha
507310
asked Jan 18 at 18:55
dyukhadyukha
507310
asked Jan 18 at 18:55
dyukhadyukha
507310
507310
1
I do believe helper functions are still the right way to do; but what about macros?
– raina77ow
Jan 18 at 18:57
1
Macros - absolutely no. I don't want to pollute defines for some local stuff (and I can accidentally override some defines).
– dyukha
Jan 18 at 18:59
Meh, move it into its own method returning a bool.
– Will
Jan 18 at 18:59
Please update your first example making it clear how/if the first pass is different
– Lyndon White
Jan 19 at 0:24
@LyndonWhite, Sorry, I don't understand you. It's not different, it's the same pass as the others.
– dyukha
Jan 19 at 0:25
|
show 1 more comment
1
I do believe helper functions are still the right way to do; but what about macros?
– raina77ow
Jan 18 at 18:57
1
Macros - absolutely no. I don't want to pollute defines for some local stuff (and I can accidentally override some defines).
– dyukha
Jan 18 at 18:59
Meh, move it into its own method returning a bool.
– Will
Jan 18 at 18:59
Please update your first example making it clear how/if the first pass is different
– Lyndon White
Jan 19 at 0:24
@LyndonWhite, Sorry, I don't understand you. It's not different, it's the same pass as the others.
– dyukha
Jan 19 at 0:25
1
1
I do believe helper functions are still the right way to do; but what about macros?
– raina77ow
Jan 18 at 18:57
I do believe helper functions are still the right way to do; but what about macros?
– raina77ow
Jan 18 at 18:57
1
1
Macros - absolutely no. I don't want to pollute defines for some local stuff (and I can accidentally override some defines).
– dyukha
Jan 18 at 18:59
Macros - absolutely no. I don't want to pollute defines for some local stuff (and I can accidentally override some defines).
– dyukha
Jan 18 at 18:59
Meh, move it into its own method returning a bool.
– Will
Jan 18 at 18:59
Meh, move it into its own method returning a bool.
– Will
Jan 18 at 18:59
Please update your first example making it clear how/if the first pass is different
– Lyndon White
Jan 19 at 0:24
Please update your first example making it clear how/if the first pass is different
– Lyndon White
Jan 19 at 0:24
@LyndonWhite, Sorry, I don't understand you. It's not different, it's the same pass as the others.
– dyukha
Jan 19 at 0:25
@LyndonWhite, Sorry, I don't understand you. It's not different, it's the same pass as the others.
– dyukha
Jan 19 at 0:25
|
show 1 more comment
1 Answer
1
active
oldest
votes
The direct simplification of your code is:
while (
some_very_long_computation &&
another_very_long_computation
) {
...
}
If you want to keep the variables a and b:
bool a, b;
while (
(a = some_very_long_computation) &&
(b = another_very_long_computation)
) {
...
}
If you don't want to put the conditions into the while condition:
while (true) {
bool a = some_very_long_computation;
bool b = another_very_long_computation;
if (!(a && b)) {
break;
}
...
}
You could also create helper lambdas (which have access to local variables):
auto fa = [&]() { return some_very_long_computation; };
auto fb = [&]() { return another_very_long_computation; };
while (fa() && fb()) {
...
}
answered Jan 19 at 0:38
melpomenemelpomene
59.6k54692
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
The direct simplification of your code is:
while (
some_very_long_computation &&
another_very_long_computation
) {
...
}
If you want to keep the variables a and b:
bool a, b;
while (
(a = some_very_long_computation) &&
(b = another_very_long_computation)
) {
...
}
If you don't want to put the conditions into the while condition:
while (true) {
bool a = some_very_long_computation;
bool b = another_very_long_computation;
if (!(a && b)) {
break;
}
...
}
You could also create helper lambdas (which have access to local variables):
auto fa = [&]() { return some_very_long_computation; };
auto fb = [&]() { return another_very_long_computation; };
while (fa() && fb()) {
...
}
answered Jan 19 at 0:38
melpomenemelpomene
59.6k54692
add a comment |
The direct simplification of your code is:
while (
some_very_long_computation &&
another_very_long_computation
) {
...
}
If you want to keep the variables a and b:
bool a, b;
while (
(a = some_very_long_computation) &&
(b = another_very_long_computation)
) {
...
}
If you don't want to put the conditions into the while condition:
while (true) {
bool a = some_very_long_computation;
bool b = another_very_long_computation;
if (!(a && b)) {
break;
}
...
}
You could also create helper lambdas (which have access to local variables):
auto fa = [&]() { return some_very_long_computation; };
auto fb = [&]() { return another_very_long_computation; };
while (fa() && fb()) {
...
}
answered Jan 19 at 0:38
melpomenemelpomene
59.6k54692
add a comment |
The direct simplification of your code is:
while (
some_very_long_computation &&
another_very_long_computation
) {
...
}
If you want to keep the variables a and b:
bool a, b;
while (
(a = some_very_long_computation) &&
(b = another_very_long_computation)
) {
...
}
If you don't want to put the conditions into the while condition:
while (true) {
bool a = some_very_long_computation;
bool b = another_very_long_computation;
if (!(a && b)) {
break;
}
...
}
You could also create helper lambdas (which have access to local variables):
auto fa = [&]() { return some_very_long_computation; };
auto fb = [&]() { return another_very_long_computation; };
while (fa() && fb()) {
...
}
answered Jan 19 at 0:38
melpomenemelpomene
59.6k54692
The direct simplification of your code is:
while (
some_very_long_computation &&
another_very_long_computation
) {
...
}
If you want to keep the variables a and b:
bool a, b;
while (
(a = some_very_long_computation) &&
(b = another_very_long_computation)
) {
...
}
If you don't want to put the conditions into the while condition:
while (true) {
bool a = some_very_long_computation;
bool b = another_very_long_computation;
if (!(a && b)) {
break;
}
...
}
You could also create helper lambdas (which have access to local variables):
auto fa = [&]() { return some_very_long_computation; };
auto fb = [&]() { return another_very_long_computation; };
while (fa() && fb()) {
...
}
answered Jan 19 at 0:38
melpomenemelpomene
59.6k54692
answered Jan 19 at 0:38
melpomenemelpomene
59.6k54692
answered Jan 19 at 0:38
melpomenemelpomene
59.6k54692
answered Jan 19 at 0:38
melpomenemelpomene
59.6k54692
59.6k54692
add a comment |
add a comment |
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1
I do believe helper functions are still the right way to do; but what about macros?
– raina77ow
Jan 18 at 18:57
1
Macros - absolutely no. I don't want to pollute defines for some local stuff (and I can accidentally override some defines).
– dyukha
Jan 18 at 18:59
Meh, move it into its own method returning a bool.
– Will
Jan 18 at 18:59
Please update your first example making it clear how/if the first pass is different
– Lyndon White
Jan 19 at 0:24
@LyndonWhite, Sorry, I don't understand you. It's not different, it's the same pass as the others.
– dyukha
Jan 19 at 0:25