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Diffstat (limited to 'test/gourdinl/c/enum1.c')
| -rw-r--r-- | test/gourdinl/c/enum1.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/test/gourdinl/c/enum1.c b/test/gourdinl/c/enum1.c new file mode 100644 index 00000000..d1f6b48d --- /dev/null +++ b/test/gourdinl/c/enum1.c @@ -0,0 +1,52 @@ +/* enum1.c -- Starting to use enumerated types: Printing for each + * day of the week, today, yesterday, and tomorrow, both + * as a string and as a number. + */ + +#include <stdio.h> + +/* Introducing an enumerated data type */ +enum days {monday,tuesday,wednesday,thursday,friday,saturday,sunday}; +typedef enum days days; // This allows us to use "days" as an abbreviation + // for "enum days" + +/* Two useful functions */ +days yesterday(days today){ + return (today+6)%7; +} +days tomorrow(days today){ + return (today+1)%7; +} + +// A useful array: thedays is an array of constant (i.e you cannot +// modify them) pointers to constant (i.e. you cannot modify them) strings +const char * const thedays[] = + {"monday", "tuesday", "wednesday", "thursday", + "friday", "saturday", "sunday"}; + +int main(void){ + days today; + + printf("today \tyesterday \ttomorrow\n" + "============================================\n"); + for (today=monday;today<=sunday;today++) + printf("%s = %d \t %s = %d \t %s = %d\n", + thedays[today], today, + thedays[yesterday(today)], yesterday(today), + thedays[tomorrow(today)], tomorrow(today)); +} + +/* + The output is: + +today yesterday tomorrow +============================================ +monday = 0 sunday = 6 tuesday = 1 +tuesday = 1 monday = 0 wednesday = 2 +wednesday = 2 tuesday = 1 thursday = 3 +thursday = 3 wednesday = 2 friday = 4 +friday = 4 thursday = 3 saturday = 5 +saturday = 5 friday = 4 sunday = 6 +sunday = 6 saturday = 5 monday = 0 + +*/ |