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| author | Fuwn <[email protected]> | 2024-04-07 23:18:32 -0700 |
|---|---|---|
| committer | Fuwn <[email protected]> | 2024-04-07 23:18:32 -0700 |
| commit | c1b6ffe70bd281c6c230fd63fabcaac2aff47514 (patch) | |
| tree | e8af3b1782a7cd0754590ed618fddc1bdb9b7385 /chapter9/useful.h | |
| download | dscode-main.tar.xz dscode-main.zip | |
Diffstat (limited to 'chapter9/useful.h')
| -rw-r--r-- | chapter9/useful.h | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/chapter9/useful.h b/chapter9/useful.h new file mode 100644 index 0000000..25dd03e --- /dev/null +++ b/chapter9/useful.h @@ -0,0 +1,46 @@ +// FILE: useful.h
+// PROVIDES: A toolkit of useful functions for random numbers and displays.
+// Note that these are in the global namespace.
+//
+// FUNCTIONS in the toolkit:
+// double random_fraction( )
+// Postcondition: The return value is a random real number in the closed
+// interval [0..1] (including the endpoints).
+//
+// double random_real(double low, double high)
+// Precondition: low <= high.
+// Postcondition: The return value is a random real number in the closed
+// interval [low..high] (including the endpoints).
+//
+// void display(double x)
+// Postcondition: The function has written one line of output to the
+// standard ouput, with a vertical bar in the middle. If x is positive,
+// then approximately x stars are printed to the right of the vertical
+// bar. If x is negative, then approximately -x stars are printed to the
+// left of the vertical bar. If the absolute value of x is more than
+// 39, then only 39 stars are printed.
+// Examples:
+// display(8) prints: |********
+// display(-4) prints: ****|
+//
+// void eat_line( )
+// Postcondition: Up to next newline has been read and discarded from cin.
+//
+// bool inquire(const char query[ ])
+// Precondition: query is a null-terminated string of characters.
+// Postcondition: query has been printed, and a one-line response read
+// from the user. The function returns true if the user's response begins
+// with 'Y' or 'y', and returns false if the user's response begins with
+// 'N' or 'n'. (If the response begins with some other letter, then the
+// query is repeated.)
+
+#ifndef USEFUL_H // Prevent duplicate definition
+#define USEFUL_H
+
+ double random_fraction( );
+ double random_real(double low, double high);
+ void display(double x);
+ void eat_line( );
+ bool inquire(const char query[ ]);
+
+#endif
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