Exercise 1-17. Write a program to print all input lines that are longer than 80 characters. Approach This exercise is a direct application of the getline / main pattern introduced in K&R Section 1.9 — but now with a filter condition added to main. The key insight is that getline already returns the line length, …
Exercise 1-16. Revise the main routine of the longest-line program so it will correctly print the length of arbitrarily long input lines, and as much as possible of the text. The K&R longest-line program (Section 1.9) stores each input line in a fixed buffer of MAXLINE characters. That design silently truncates any line longer than …
Exercise 1-15. Rewrite the temperature conversion program of Section 1.2 to use a function. Section 1.2 of K&R embeds the conversion formula directly inside main. It works — but it ties the formula to one spot in the code. This exercise asks you to extract that logic into a separate function called celsius. The payoff …
Exercise 1-14. Write a program to print a histogram of the frequencies of different characters in its input. Approach The key insight here is one of the most elegant idioms in C: a character read from getchar() is already an integer — its ASCII value. That value falls in the range 0–127, so it can …
Exercise 1-13. Write a program to print a histogram of the lengths of words in its input. It is easy to draw the histogram with the bars horizontal; a vertical orientation is more challenging. Approach The program breaks into two clear phases: counting word lengths, then rendering the histogram. Counting reuses the IN/OUT state machine …
Exercise 1-12. Write a program that prints its input one word per line. Approach A word is any contiguous run of non-whitespace characters; spaces, tabs, and newlines are all separators. The challenge is not reading words — it is knowing when to emit the newline that separates them in the output. The solution borrows the …