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Diffstat (limited to 'games/arithmetic/arithmetic.c')
| -rw-r--r-- | games/arithmetic/arithmetic.c | 393 |
1 files changed, 0 insertions, 393 deletions
diff --git a/games/arithmetic/arithmetic.c b/games/arithmetic/arithmetic.c deleted file mode 100644 index 68cd045..0000000 --- a/games/arithmetic/arithmetic.c +++ /dev/null @@ -1,393 +0,0 @@ -/* - * Copyright (c) 1989, 1993 - * The Regents of the University of California. All rights reserved. - * - * This code is derived from software contributed to Berkeley by - * Eamonn McManus of Trinity College Dublin. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by the University of - * California, Berkeley and its contributors. - * 4. Neither the name of the University nor the names of its contributors - * may be used to endorse or promote products derived from this software - * without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - */ - -#ifndef lint -static const char copyright[] = -"@(#) Copyright (c) 1989, 1993\n\ - The Regents of the University of California. All rights reserved.\n"; -#endif /* not lint */ - -#ifndef lint -#if 0 -static char sccsid[] = "@(#)arithmetic.c 8.1 (Berkeley) 5/31/93"; -#endif -static const char rcsid[] = - "$FreeBSD$"; -#endif /* not lint */ - -/* - * By Eamonn McManus, Trinity College Dublin <emcmanus@cs.tcd.ie>. - * - * The operation of this program mimics that of the standard Unix game - * `arithmetic'. I've made it as close as I could manage without examining - * the source code. The principal differences are: - * - * The method of biasing towards numbers that had wrong answers in the past - * is different; original `arithmetic' seems to retain the bias forever, - * whereas this program lets the bias gradually decay as it is used. - * - * Original `arithmetic' delays for some period (3 seconds?) after printing - * the score. I saw no reason for this delay, so I scrapped it. - * - * There is no longer a limitation on the maximum range that can be supplied - * to the program. The original program required it to be less than 100. - * Anomalous results may occur with this program if ranges big enough to - * allow overflow are given. - * - * I have obviously not attempted to duplicate bugs in the original. It - * would go into an infinite loop if invoked as `arithmetic / 0'. It also - * did not recognise an EOF in its input, and would continue trying to read - * after it. It did not check that the input was a valid number, treating any - * garbage as 0. Finally, it did not flush stdout after printing its prompt, - * so in the unlikely event that stdout was not a terminal, it would not work - * properly. - */ - -#include <sys/types.h> -#include <sys/signal.h> -#include <ctype.h> -#include <stdio.h> -#include <string.h> -#include <stdlib.h> -#include <time.h> -#include <unistd.h> - -const char keylist[] = "+-x/"; -const char defaultkeys[] = "+-"; -const char *keys = defaultkeys; -int nkeys = sizeof(defaultkeys) - 1; -int rangemax = 10; -int nright, nwrong; -time_t qtime; -#define NQUESTS 20 - -static void usage(void); -int getrandom(int, int, int); -void intr(int); -int opnum(int); -void penalise(int, int, int); -int problem(void); -void showstats(void); - -/* - * Select keys from +-x/ to be asked addition, subtraction, multiplication, - * and division problems. More than one key may be given. The default is - * +-. Specify a range to confine the operands to 0 - range. Default upper - * bound is 10. After every NQUESTS questions, statistics on the performance - * so far are printed. - */ -int -main(int argc, char **argv) -{ - int ch, cnt; - - /* Revoke setgid privileges */ - setgid(getgid()); - - while ((ch = getopt(argc, argv, "r:o:")) != -1) - switch(ch) { - case 'o': { - const char *p; - - for (p = keys = optarg; *p; ++p) - if (!index(keylist, *p)) { - (void)fprintf(stderr, - "arithmetic: unknown key.\n"); - exit(1); - } - nkeys = p - optarg; - break; - } - case 'r': - if ((rangemax = atoi(optarg)) <= 0) { - (void)fprintf(stderr, - "arithmetic: invalid range.\n"); - exit(1); - } - break; - case '?': - default: - usage(); - } - if (argc -= optind) - usage(); - - /* Seed the random-number generator. */ - srandomdev(); - - (void)signal(SIGINT, intr); - - /* Now ask the questions. */ - for (;;) { - for (cnt = NQUESTS; cnt--;) - if (problem() == EOF) - exit(0); - showstats(); - } - /* NOTREACHED */ -} - -/* Handle interrupt character. Print score and exit. */ -void -intr(int sig) -{ - sig = 0; - showstats(); - exit(0); -} - -/* Print score. Original `arithmetic' had a delay after printing it. */ -void -showstats(void) -{ - if (nright + nwrong > 0) { - (void)printf("\n\nRights %d; Wrongs %d; Score %d%%", - nright, nwrong, (int)(100L * nright / (nright + nwrong))); - if (nright > 0) - (void)printf("\nTotal time %ld seconds; %.1f seconds per problem\n\n", - (long)qtime, (float)qtime / nright); - } - (void)printf("\n"); -} - -/* - * Pick a problem and ask it. Keeps asking the same problem until supplied - * with the correct answer, or until EOF or interrupt is typed. Problems are - * selected such that the right operand and either the left operand (for +, x) - * or the correct result (for -, /) are in the range 0 to rangemax. Each wrong - * answer causes the numbers in the problem to be penalised, so that they are - * more likely to appear in subsequent problems. - */ -int -problem(void) -{ - char *p; - time_t start, finish; - int left, op, right, result; - char line[80]; - - left = 0; - right = 0; - result = 0; - op = keys[random() % nkeys]; - if (op != '/') - right = getrandom(rangemax + 1, op, 1); -retry: - /* Get the operands. */ - switch (op) { - case '+': - left = getrandom(rangemax + 1, op, 0); - result = left + right; - break; - case '-': - result = getrandom(rangemax + 1, op, 0); - left = right + result; - break; - case 'x': - left = getrandom(rangemax + 1, op, 0); - result = left * right; - break; - case '/': - right = getrandom(rangemax, op, 1) + 1; - result = getrandom(rangemax + 1, op, 0); - left = right * result + random() % right; - break; - } - - /* - * A very big maxrange could cause negative values to pop - * up, owing to overflow. - */ - if (result < 0 || left < 0) - goto retry; - - (void)printf("%d %c %d = ", left, op, right); - (void)fflush(stdout); - (void)time(&start); - - /* - * Keep looping until the correct answer is given, or until EOF or - * interrupt is typed. - */ - for (;;) { - if (!fgets(line, sizeof(line), stdin)) { - (void)printf("\n"); - return(EOF); - } - for (p = line; *p && isspace(*p); ++p); - if (!isdigit(*p)) { - (void)printf("Please type a number.\n"); - continue; - } - if (atoi(p) == result) { - (void)printf("Right!\n"); - ++nright; - break; - } - /* Wrong answer; penalise and ask again. */ - (void)printf("What?\n"); - ++nwrong; - penalise(right, op, 1); - if (op == 'x' || op == '+') - penalise(left, op, 0); - else - penalise(result, op, 0); - } - - /* - * Accumulate the time taken. Obviously rounding errors happen here; - * however they should cancel out, because some of the time you are - * charged for a partially elapsed second at the start, and some of - * the time you are not charged for a partially elapsed second at the - * end. - */ - (void)time(&finish); - qtime += finish - start; - return(0); -} - -/* - * Here is the code for accumulating penalties against the numbers for which - * a wrong answer was given. The right operand and either the left operand - * (for +, x) or the result (for -, /) are stored in a list for the particular - * operation, and each becomes more likely to appear again in that operation. - * Initially, each number is charged a penalty of WRONGPENALTY, giving it that - * many extra chances of appearing. Each time it is selected because of this, - * its penalty is decreased by one; it is removed when it reaches 0. - * - * The penalty[] array gives the sum of all penalties in the list for - * each operation and each operand. The penlist[] array has the lists of - * penalties themselves. - */ - -int penalty[sizeof(keylist) - 1][2]; -struct penalty { - int value, penalty; /* Penalised value and its penalty. */ - struct penalty *next; -} *penlist[sizeof(keylist) - 1][2]; - -#define WRONGPENALTY 5 /* Perhaps this should depend on maxrange. */ - -/* - * Add a penalty for the number `value' to the list for operation `op', - * operand number `operand' (0 or 1). If we run out of memory, we just - * forget about the penalty (how likely is this, anyway?). - */ -void -penalise(int value, int op, int operand) -{ - struct penalty *p; - - op = opnum(op); - if ((p = (struct penalty *)malloc((u_int)sizeof(*p))) == NULL) - return; - p->next = penlist[op][operand]; - penlist[op][operand] = p; - penalty[op][operand] += p->penalty = WRONGPENALTY; - p->value = value; -} - -/* - * Select a random value from 0 to maxval - 1 for operand `operand' (0 or 1) - * of operation `op'. The random number we generate is either used directly - * as a value, or represents a position in the penalty list. If the latter, - * we find the corresponding value and return that, decreasing its penalty. - */ -int -getrandom(int maxval, int op, int operand) -{ - int value; - struct penalty **pp, *p; - - op = opnum(op); - value = random() % (maxval + penalty[op][operand]); - - /* - * 0 to maxval - 1 is a number to be used directly; bigger values - * are positions to be located in the penalty list. - */ - if (value < maxval) - return(value); - value -= maxval; - - /* - * Find the penalty at position `value'; decrement its penalty and - * delete it if it reaches 0; return the corresponding value. - */ - for (pp = &penlist[op][operand]; (p = *pp) != NULL; pp = &p->next) { - if (p->penalty > value) { - value = p->value; - penalty[op][operand]--; - if (--(p->penalty) <= 0) { - p = p->next; - (void)free((char *)*pp); - *pp = p; - } - return(value); - } - value -= p->penalty; - } - /* - * We can only get here if the value from the penalty[] array doesn't - * correspond to the actual sum of penalties in the list. Provide an - * obscure message. - */ - (void)fprintf(stderr, "arithmetic: bug: inconsistent penalties\n"); - exit(1); - /* NOTREACHED */ -} - -/* Return an index for the character op, which is one of [+-x/]. */ -int -opnum(int op) -{ - char *p; - - if (op == 0 || (p = index(keylist, op)) == NULL) { - (void)fprintf(stderr, - "arithmetic: bug: op %c not in keylist %s\n", op, keylist); - exit(1); - } - return(p - keylist); -} - -/* Print usage message and quit. */ -static void -usage(void) -{ - (void)fprintf(stderr, "usage: arithmetic [-o +-x/] [-r range]\n"); - exit(1); -} |
