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Write the program expr , which evaluates a reverse Polish expression from the command line, where each operator or operand is a separate argument. For example, expr 2 3 4 + * evaluates 2 X (3 + 4). Solution by Lars Wirzenius Note: Lars uses EXIT_FAILURE on error. As far as I can tell, this is the only thing which makes this a Category 1, rather than Category 0, solution. /* * Solution to exercis..

Rewrite the routines day_of_year and month_day with pointers instead of indexing. Solutions by Lars Wirzenius and Gregory Pietsch Here's Lars's solution: /* * A solution to exercise 5-9 in K&R2, page 114: * * Rewrite the routines day_of_year and month_day with pointers * instead of indexing. * * Lars Wirzenius */ #include static char daytab[2][13] = { {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, ..

There is no error-checking in day_of_year or month_day. Remedy this defect. Solution by Lars Wirzenius /* * A solution to exercise 5-8 in K&R2, page 112: * * There is no error checking in day_of_year or month_day. Remedy * this defect. * * The error to check for is invalid argument values. That is simple, what's * hard is deciding what to do in case of error. In the real world, I would * use the..

Rewrite readlines to store lines in an array supplied by main , rather than calling alloc to maintain storage. How much faster is the program? Solution by Steven Huang /* K&R Exercise 5-7 */ /* Steven Huang */ #include #include #include #include #define TRUE 1 #define FALSE 0 #define MAXLINES 5000 /* maximum number of lines */ #define MAXLEN 1000 /* maximum length of a line */ char *lineptr[MAXL..

Rewrite appropriate programs from earlier chapters and exercises with pointers instead of array indexing. Good possibilities include getline (Chapters 1 and 4), atoi , itoa , and their variants (Chapters 2, 3, and 4), reverse (Chapter 3), and strindex and getop (Chapter 4). Solution by Gregory Pietsch /* Gregory Pietsch ex. 5-6 dated 2001-01-29 */ #include #include #include /* getline: get line ..

Write versions of the library functions strncpy , strncat , and strncmp , which operate on at most the first n characters of their argument strings. For example, strncpy(s,t,n) copies at most n characters of t to s . Full descriptions are in Appendix B. Solution by Lars Wirzenius Note: Lars uses EXIT_FAILURE in his test code, but not in the actual solution code. As far as I can tell, then, this ..

Write the function strend(s,t) , which returns 1 if the string t occurs at the end of the string s , and zero otherwise. Solution by Bryan Williams /* Exercise 5-4. Write the function strend(s,t), which returns 1 if the string t occurs at the end of the string s, and zero otherwise. Author : Bryan Williams */ int strlen(char *s) /* added by RJH; source: K&R p99 */ { int n; for(n = 0; *s != '\0';..

Write a pointer version of the function strcat that we showed in Chapter 2: strcat(s,t) copies the string t to the end of s . Solution by Richard Heathfield /* ex 5-3, p107 */ #include void strcpy(char *s, char *t) { while(*s++ = *t++); } void strcat(char *s, char *t) { while(*s) { ++s; } strcpy(s, t); } int main(void) { char testbuff[128]; char *test[] = { "", "1", "12", "123", "1234" }; size_t..

Write getfloat , the floating-point analog of getint . What type does getfloat return as its function value? Solutions by Chris Mears and Gregory Pietsch Here is Chris's solution: /* * Exercise 5-2 from The C Programming Language, 2nd edition, by Kernighan * and Ritchie. * * "Write getfloat, the floating-point analog of getint. What type does * getfloat return as its function value?" */ /* * Her..