Minor fixes to 1996/schweikh1
The author noted in the Makefile that for Solaris the compiler flag -I/usr/include should be included so I have added that. As well I updated the README.md - formatting fixes (possibly typos as well but no longer sure).
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@@ -98,7 +98,7 @@ CDEFINE=
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# Include files that are needed to compile
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# Include files that are needed to compile
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#
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#
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#CINCLUDE=
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#CINCLUDE=
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CINCLUDE= -I.
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CINCLUDE= -I. -I/usr/include
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#CINCLUDE= -include stdlib.h
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#CINCLUDE= -include stdlib.h
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#CINCLUDE= -include stdio.h
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#CINCLUDE= -include stdio.h
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#CINCLUDE= -include stdlib.h -include stdio.h
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#CINCLUDE= -include stdlib.h -include stdio.h
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+79
-68
@@ -12,99 +12,110 @@
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make all
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make all
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### To run
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## To run:
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./schweikh1
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./schweikh1
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## Judges' comments
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## Judges' comments:
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Look at the source. There is something very odd going on here.
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Look at the source. There is something very odd going on here.
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Where does the real code come from if everything is a C pre-processor
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Where does the real code come from if everything is a C pre-processor
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statement?
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statement?
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Clearly this is either the Best Use or the Worst Abuse of the
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Clearly this is either the Best Use or the Worst Abuse of the
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C Preprocessor that the judges have seen this year!
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C Preprocessor that the judges have seen this year!
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## Author's comments
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## Author's comments:
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What this program does
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What this program does
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----------------------
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----------------------
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This program is an implementation of an algorithm that calculates
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This program is an implementation of an algorithm that calculates
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the date of the Sunday following the first full moon after the
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the date of the Sunday following the first full moon after the
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spring equinoxe. (Also known as "Easter", defined this way by the
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spring equinoxe. (Also known as "Easter", defined this way by the
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Nicaean Concilium in 325 Anno Domini.) The algorithm is attributed
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Nicaean Concilium in 325 Anno Domini.) The algorithm is attributed
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to the famous mathematician Carl Friedrich Gauss ["Meyers Handbuch
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to the famous mathematician Carl Friedrich Gauss ["Meyers Handbuch
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ueber das Weltall", Meyer, 5th Edition, 1973, p149] and is suitable
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ueber das Weltall", Meyer, 5th Edition, 1973, p149] and is suitable
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for anni domini within the Gregorian Calendar, that is, from 1582 AD
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for anni domini within the Gregorian Calendar, that is, from 1582 AD
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to 2199 AD:
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to 2199 AD:
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Let J be the year.
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If J is from 1582 to 1699, let M be 22, let N be 2
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If J is from 1700 to 1799, let M be 23, let N be 3
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If J is from 1800 to 1899, let M be 23, let N be 4
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If J is from 1900 to 2099, let M be 24, let N be 5
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If J is from 2100 to 2199, let M be 24, let N be 6
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Let a be the modulus of J divided by 19
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Let b be the modulus of J divided by 4
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Let c be the modulus of J divided by 7
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Let d be the modulus of (19a + M) divided by 30
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Let e be the modulus of (2b + 4c + 6d + N) divided by 7
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The interesting Sunday is either:
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Let J be the year.
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If J is from 1582 to 1699, let M be 22, let N be 2
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If J is from 1700 to 1799, let M be 23, let N be 3
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If J is from 1800 to 1899, let M be 23, let N be 4
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If J is from 1900 to 2099, let M be 24, let N be 5
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If J is from 2100 to 2199, let M be 24, let N be 6
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Let a be the modulus of J divided by 19
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Let b be the modulus of J divided by 4
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Let c be the modulus of J divided by 7
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Let d be the modulus of (19a + M) divided by 30
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Let e be the modulus of (2b + 4c + 6d + N) divided by 7
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The interesting Sunday is either
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March 22 + d + e or
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March 22 + d + e or
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April d + e - 9 (only one of them is a valid date)
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April d + e - 9 (only one of them is a valid date)
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with the following exceptions:
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with the following exceptions:
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April 26 must always be changed to April 19
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April 26 must always be changed to April 19
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April 25 must be changed to April 18 if d is 28 and a greater than 10
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April 25 must be changed to April 18 if d is 28 and a greater than 10
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Example: J = 1962, M = 24, N = 5
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### Example:
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J = 1962, M = 24, N = 5
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a = J % 19 = 5
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a = J % 19 = 5
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b = J % 4 = 2
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b = J % 4 = 2
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c = J % 7 = 2
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c = J % 7 = 2
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d = 119 % 30 = 29
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d = 119 % 30 = 29
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e = 191 % 7 = 2
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e = 191 % 7 = 2
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March 53 is invalid, so the result is April 22 1962
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March 53 is invalid, so the result is April 22 1962
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Why I think this is obfuscated
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Why I think this is obfuscated
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------------------------------
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------------------------------
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Apart from the calculation of the Easter date, the definition *and*
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Apart from the calculation of the Easter date, the definition *and*
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calculation of which are obfuscations in their own right,
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calculation of which are obfuscations in their own right,
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obfuscation lurks in many places. Look at those macro identifiers.
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obfuscation lurks in many places. Look at those macro identifiers.
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What can be more obvious than a program that explicitly mentions the
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What can be more obvious than a program that explicitly mentions the
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grammatical constructs it is composed of? If you look at K&RII A.9.3
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grammatical constructs it is composed of? If you look at K&RII A.9.3
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you will find that a compound statement consists of an opening brace
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you will find that a compound statement consists of an opening brace
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followed by a declaration list followed by a semicolon followed by a
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followed by a declaration list followed by a semicolon followed by a
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statement list followed by another semicolon and a closing brace.
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statement list followed by another semicolon and a closing brace.
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Nobody can learn that by heart so I gently remind the reader by
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Nobody can learn that by heart so I gently remind the reader by
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defining a macro that expresses this clearly (line 25). This goes up
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defining a macro that expresses this clearly (line 25). This goes up
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to the definition of a translation unit. Unfortunately, due to the
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to the definition of a translation unit. Unfortunately, due to the
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IOCCC's size restrictions, I had to abbreviate some syntactic
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IOCCC's size restrictions, I had to abbreviate some syntactic
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elements. "ae" actually reads "assignment expression". I had to stop
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elements. "ae" actually reads "assignment expression". I had to stop
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at some arbitrary point, so don't waste your time trying to find out
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at some arbitrary point, so don't waste your time trying to find out
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how preprocessing tokens form type qualifier lists, cast expressions
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how preprocessing tokens form type qualifier lists, cast expressions
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or direct abstract declarators. Assuming the reader knows about
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or direct abstract declarators. Assuming the reader knows about
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these easy to remember language elements is justified in my opinion.
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these easy to remember language elements is justified in my opinion.
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The moral:
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### The moral:
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Try to be as precise as can be and no one will comprehend what you mean.
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Try to be as precise as can be and no one will comprehend what you mean.
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The formula:
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#### The formula:
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comprehension = 1/(2**precision)
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The interpretation:
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comprehension = 1/(2**precision)
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"Say nothing and everybody will understand."
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The -I/usr/include in the build file is needed by gcc on Solaris because
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#### The interpretation:
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gcc's "fixed" header in gcc-lib/sparc-sun-solaris2.5/2.7.2/include/errno.h
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is broken (sort of) because it has *two* identical extern
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declarations of errno. This leads to an error due to the
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redefinition of main. The -I option makes sure the working
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/usr/include/errno.h is found first, which shouldn't harm on other
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systems.
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Usage
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"Say nothing and everybody will understand."
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-----
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The program is run without arguments. It prints all dates in order.
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The `-I/usr/include` in the build file is needed by gcc on Solaris because
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gcc's "fixed" header in gcc-lib/sparc-sun-solaris2.5/2.7.2/include/errno.h
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is broken (sort of) because it has *two* identical extern
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declarations of errno. This leads to an error due to the
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redefinition of main. The `-I` option makes sure the working
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/usr/include/errno.h is found first, which shouldn't harm on other
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systems.
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Usage
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-----
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The program is run without arguments. It prints all dates in order.
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