Lecture 12: October 21, 2019

Reading: C text, §8, 9
Due: Extra Credit #1: due October 21, 2019; Homework #2, due October 24, 2019

1. Greetings and felicitations!
   1. General: there are a couple of aids to learning the Bourne-Again shell, bash(1)
   2. Homework 2: I posted an announcement to answer some of the questions.
   3. Extra Credit assignment, problem 2; you just need to give the command, not execute it; but you can replace “/usr” with “/home” if you like.
2. Operators
   1. Comma operator ,; use while(printf("> "), scanf("%d", &x) != EOF) and y = 3; x = y++, 20
   2. Order of evaluation of function arguments; use i = 10; f(i, ++i) and f(i, i++)
3. C characters
   1. Characters as integers and numbers (caesar-enc.c, caesar-dec.c)
4. String library functions
   1. Prototypes in include file string.h
   2. String length: strlen(str)
   3. String copy: strcpy(dest, src); strncpy(dest, src, number_chars)
   4. String catenation: strcat(dest, src); strncat(dest, src, number_chars)
   5. String comparison: strcmp(dest, src); strncmp(dest, src, number_chars)
5. Recursive greatest common divisor
   1. Go through Euclidean algorithm for computing gcd
   2. Walk through function gcd, with m = 4 and n = 6
   3. Do it again with m = 126 and n = 28
   4. Go through program gcd.c

Matt Bishop Office: 2209 Watershed Sciences Phone: +1 (530) 752-8060 Email: mabishop@ucdavis.edu

ECS 36A, Programming and Problem Solving Version of October 21, 2019 at 6:04PM

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