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 1-11. How would you test the word count program? What kinds of input are most likely to uncover bugs if there are any? Exercise 1-11 has no new program to write. It asks you to think like a tester — to look at the word count program K&R presented in Section 1.5.4 and design …
Exercise 1-8. Write a program to count blanks, tabs, and newlines. Approach The solution maintains three independent counters and reads one character at a time using the canonical getchar() loop. The key design decision is using three separate if statements rather than else if. In this case a character can only ever be one thing …
Exercise 1-7. Write a program to print the value of EOF. This is one of those exercises that looks trivial — one printf and you’re done — but it opens the door to one of the most important design decisions in the C standard library. Before you can really understand why Chapter 1’s input loops …
Exercise 1-4. Write a program to print the corresponding Celsius to Fahrenheit table. Approach K&R Chapter 1 opens with a Fahrenheit-to-Celsius table, converting F values to Celsius using C = 5 × (F − 32) / 9. This exercise asks for the inverse: step through Celsius values (0, 20, 40, …, 300) and compute the …