C PROGRAMMING
Vishal Vij
recprogrammingduethursday14thnovember2013at1100am.zipintmath.h
/* * The "intmath.h" header defines the following five integer arithmetic * functions: * int add(int x, int y) - returns the sum of x and y * int subtract(int x, int y) - returns the subtraction of y from x * int divide(int n, int d) - returns the integer division of n by d * int modulo(int n, int d) - returns the remainder when n is divided by d * int division(int n, int d, int *r) - returns the integer division of n by d * and uses r to record the remainder * * Implementations of these functions check for overflow of the range of * integers as described below. * * Implementors of these functions can only use the built-in arithmetic * operators ++, -- and unary - negation. */ #ifndef _INTMATH_H /* check if "intmath.h" is already included */ #define _INTMATH_H /* it is not included; define it */ /* * int add(x, y) * * This function returns the sum of two integers (x and y) - adding y to x. * * The function checks for integer overflow. If the result of the addition of * the two integers would exceed the defined range for integers then the value * of errno is set to ERANGE and the function returns -1. * * It is the responsibility of users of this function to test for errno * correctly and distinguish between the two cases: (1) where -1 is the valid * result of the sum of two integers, and (2) when integer overflow would have * occurred. * See: http://man7.org/linux/man-pages/man3/errno.3.html for information on * errno * * Parameters: * x - the integer to add y to * y - the integer to add to x * Return: * the result of adding y to x */ int add(int x, int y); /* * int subtract(int x, int y) * * This function returns the difference between two integers (x and y) - the * result of subtracting y from x. * * The function checks for integer overflow. If the result of the subtraction of * y from x would exceed the defined range for integers then the value * of errno is set to ERANGE and the function returns -1. * * It is the responsibility of users of this function to test for errno * correctly and distinguish between the two cases: (1) where -1 is the valid * result of the subtraction of y from x, and (2) when integer overflow would * have occurred. * See: http://man7.org/linux/man-pages/man3/errno.3.html for information on * * Parameters: * x - the integer subtract y from * y - the integer to subtract from x * Return: * the result of subtracting y from x */ int subtract(int x, int y); /* * int divide(int n, int d) * * This function returns the result of integer division of the numerator (n) by * the denominator (d). * * The function checks for division by 0. If d is 0 then the function * returns -1 and errno is set to EDOM. * There is also one case when the division can cause integer * overflow. In which case, the function returns -1 and errno is set to ERANGE. * * It is the responsibility of users of this function to test for errno * correctly and distinguish between the two cases: (1) where -1 is the valid * result of the division of n by d, and (2) when division by 0 or * integer overflow would have occurred. * See: http://man7.org/linux/man-pages/man3/errno.3.html for information on * * Parameters: * n - the numerator of integer division * d - the denominator of integer division * Return: * the result of integer division of n by d */ int divide(int n, int d); /* * int modulo(int n, int d) * * This function returns the remainder of integer after division of the * numerator (n) by the denominator (d). * * The function checks for division by 0. If d is 0 then the function * returns 0 and errno is set to EDOM. * There is also one case when the division can cause integer * overflow. In which case, the function returns 0 and errno is set to ERANGE. * * It is the responsibility of users of this function to test for errno * correctly and distinguish between the two cases: (1) where 0 is the valid * result of n modulo d, and (2) when division by 0 or integer overflow would * have occurred. * See: http://man7.org/linux/man-pages/man3/errno.3.html for information on * * Parameters: * n - the numerator of integer division * d - the denominator of integer division * Return: * the remainder after integer division of n by d */ int modulo(int n, int d); /* * int division(int n, int d, int *r) * * This function returns the result of integer division of the numerator (n) by * the denominator (d). In addition, it uses r to record the remainder of the * division. * * The function checks for division by 0. If d is 0 then the function * returns -1, errno is set to EDOM and *r will be 0. * There is also one case when the division can cause integer * overflow. In which case the function returns -1, errno is set to ERANGE and * *r will be 0. * * It is the responsibility of users of this function to test for errno * correctly and distinguish between the two cases: (1) where -1 is the valid * result of the division of n by d, and (2) when division by 0 or * integer overflow would have occurred. * See: http://man7.org/linux/man-pages/man3/errno.3.html for information on * * Parameters: * n - the numerator of integer division * d - the denominator of integer division * r - the address of integer to record the remainder after integer division * of n by d * Return: * the result ofinteger division of n by d */ int division(int n, int d, int *r); #endif /* _INTMATH_H */
utils.h
/* * The "utils.h" header defines the following three utility functions: * int getaline(char *linebuf, int bufsize) - read a line of user input into * the buffer linebuf * int split(char *s, int start, char sep, char **substrings, int max) - split * a string at the separator character sep into at most max substrings, * starting at position start * int trim(char *s, char c) - trim a string of leading and trailing sequences * of the character c, returning the position of the first non-c character * * Implementors of these functions should only use the C library function * getchar. */ #ifndef _UTILS_H /* check if "utils.h" is already included */ #define _UTILS_H /* it is not included; define it */ /* * int getaline(char* linebuf, int bufsize) * * Read a line of user input from stdin into the buffer linebuf a character at * a time. * * After successful execution of the function, linebuf will contain up to * bufsize - 1 characters from user input and will be terminated by the '\0' * character. That is, linebuf can be treated as a string of up to busize -1 * characters not including the terminator character. The buffer must NOT * contain the end of line character ('\n'). * * The library function getchar can be used to read a character at a time from * stdin. * * Parameters: * linebuf - the buffer to fill with characters from the stdin stream. linebuf * is modified by this function. * bufsize - the size of the linebuf buffer * Return: * The number of characters read from user input, -1 if there is an error. If * linebuf is filled, the number returned will be bufsize - 1 and there may be * more user input. If the number returned is 0, there was in effect no * user input (e.g. the only character entered was the new line character) */ int getaline(char* linebuf, int bufsize); /* * int split(char *s, int start, char sep, char **substrings, int max) * * Split a string, s, into at most max substrings at the given separator * character. The substrings array is used to hold pointers to the * resulting substrings of s. If s does not contain the separator character then * a pointer to the single string s will be in the substrings array. Unused * elements of the substrings buffer will be set to NULL. * * If s contains sequences of more than one separator between sequences of * non-separator characters, this function will terminate a substring at the * first separator and skip to the next non-separator character to start the * next substring. This function does *not* treat sequences of leading or * trailing separator characters as special cases. This means that, after * calling split, the first and/or last elements of the substrings array may * point to the empty string. For example, for the following inputs: * char s[]: "--ab--c--" * int start: 0 * char sep: '-' * int max: 4 * The substrings buffer will have points to the following strings: * { "", "ab", "c", "" } * * Other variations of the input string can result in empty strings at the * beginning and/or end of the substrings buffer. * * To skip leading and trailing separator characters, use trim before calling * split. If trim is used before split, and the return value of trim is used for * the start value of split, this function will correctly return 0 for a string * s that only contains separator characters. * * Parameters: * s - the input string. This function may modify s. There is no copying of * characters. * start - the position in s to start the search for separator characters. The * first substring will start from this position in s. If start is less * than 0, the number of substrings will be 0. * sep - the character at which substrings should be created * substrings - the array to populate with pointers to substrings of s. * substrings is modified by this function. Neither characters nor strings * are copied to substrings. The elements of substrings are simply pointers * to substrings of s. If there are less than max substrings, then the * remaining elements of the substrings buffer will be set to NULL. * max - the maximum number of substrings required. This should be less than * or equal to the size of the substrings buffer. * It is possible for s to contain more than max substrings, in * which case the final pointer in the substrings buffer will point to a * substring that contains one or more separator characters. * Return: * the number of pointers to strings in substrings. If s contains at * least one non-separator character and max is at least 1, the number * of substrings will be at least 1. If the number of * substrings is less than max, then the elements of substrings from * number to max - 1 will be NULL. */ int split(char *s, int start, char sep, char **substrings, int max); /* * int trim(char *s, char c) * * Trim the input string of leading and trailing sequences of the specified * character c. The return value is the position of the first character in s * that is not c. * * Parameters: * s - the input string. s may be modified by this function, there is no * copying of characters. * c - the character to trim from the beginning and end of s * Return: * the position of the first character in s that is not c. -1 if s * contains no other character than c (not including the terminator * character). */ int trim(char *s, char c); #endif /* _UTILS_H */
