base for h3

334/homework/3/chap5.txt

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+#
+# Problem lines begin with "#@".
+# For each problem line, enter your answer on the following line.
+# Do not modify this file in any way except to enter your answers.
+#
+
+#@ 1 -- enter 'a', 'b', or 'c' (don't use quotes in any answer)
+b
+#@ 2 -- enter 'a', 'b', or 'c' 
+a
+#@ 3 -- enter 'a', 'b', or 'c' 
+b
+#@ 4 -- enter 'a', 'b', or 'c' 
+a

334/homework/3/chap6.txt

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+#
+# Problem lines begin with "#@".
+# For each problem line, enter your answer on the following line.
+# Do not modify this file in any way except to enter your answers.
+#
+
+#@ 1 -- enter 'a' or 'b'  (don't use quotes in any answer)
+b
+#@ 2 -- enter 'a', 'b', or 'c' 
+a
+#@ 3 -- enter 'T' or 'F'
+F
+#@ 4 -- enter 'T' or 'F'
+F

334/homework/3/msh.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define PROMPT "msh> "
+#define EXIT_CMD "exit"
+#define MAX_BUF 121
+
+void echo(const char*);
+void remove_newline(char*);
+void exit_branch(const char*);
+
+int main(void) {
+	char buffer[MAX_BUF];
+	while(1) {
+		printf("%s", PROMPT);
+		fgets(buffer, MAX_BUF, stdin);
+		// process the input
+		remove_newline(buffer);
+		exit_branch(buffer);
+		echo(buffer);
+	}
+	return 0;
+}
+
+void echo(const char* buf) {
+	printf("%s\n", buf);
+}
+
+
+void remove_newline(char* buf) {
+	char* c = buf;
+	while(*c != '\n') { c++; }
+	*c='\0';
+}
+
+void exit_branch(const char* buf) {
+	if(strcmp(buf, EXIT_CMD)) {
+		return;
+	}
+	exit(0);
+	return; // just for gcc but exit shouldn't fail
+}