1 files changed, 144 insertions, 0 deletions
diff --git a/5.19.c b/5.19.c
new file mode 100644
index 0000000..8709df7
--- /dev/null
+++ b/5.19.c
@@ -0,0 +1,144 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+#define MAXTOKEN	100
+#define OUTLEN		1000
+#define MAXBUFF		100
+
+enum { NAME, PARENS, BRACKETS };
+enum { NO, YES };
+
+void err(char *s);
+
+int gettoken(void);
+int peaktoken(void);
+char tokentype;
+char token[MAXTOKEN];
+char prevtoken;
+char out[OUTLEN];
+
+char buff[MAXBUFF];
+static size_t top;
+
+
+void err(char *s)
+{
+	printf("fatal error: %s\n", s);
+	exit(1);
+}
+
+int gettoken(void)
+{
+	char c, *p = token;
+	char getch(void);
+	void ungetch(char);
+
+	if (prevtoken == YES) {
+		prevtoken = NO;
+		return tokentype;
+	}
+
+	while(isblank(c = getch()))
+		;
+
+	if (c == '/') { /* ignore comments */
+		if ((c = getch()) == '/') {
+			while ((c = getch()) != '\n')
+				;
+		} else if (c == '*') {
+			while (getch() != '*' || (c = getch()) != '/')
+				if (c == '*')
+					ungetch('*');
+			return gettoken();
+		} else {
+			ungetch(c);
+			c = '/';
+		}
+	}
+
+	if (c == '(') {
+		if ((c = getch()) == ')') {
+			strcpy(token, "()");
+			return tokentype = PARENS;
+		} else {
+			ungetch(c);
+			return tokentype = '(';
+		}
+	} else if (c == '[') {
+		for (*p++ = '['; (*p++ = getch()) != ']';)
+			;
+		*p = '\0';
+		return tokentype = BRACKETS;
+	} else if (isalpha(c)) {
+		for (*p++ = c; isalnum(c = getch());)
+			*p++ = c;
+		*p = '\0';
+		ungetch(c);
+		return tokentype = NAME;
+	} else {
+		return tokentype = c;
+	}
+}
+
+void ungetch(char c)
+{
+	if (top < MAXBUFF)
+		buff[top++] = c;
+	else
+		err("buff: stack overflow");
+}
+
+char getch(void)
+{
+	return (top > 0) ? buff[--top] : getchar();
+}
+
+int peaktoken()
+{
+	char type;
+
+	type = gettoken();
+	prevtoken = YES;
+	return type;
+}
+
+int main(void)
+{
+	int err;
+	char type;
+	char temp[OUTLEN + MAXTOKEN];
+
+	while (gettoken() != EOF) {
+		err = 0;
+		strcpy(out, token);
+		while ((type = gettoken()) != '\n') {
+			if (type == PARENS || type == BRACKETS ) {
+				strcat(out, token);
+			} else if (type == '*') {
+				if ((type = peaktoken()) == PARENS ||
+					type == BRACKETS)
+					sprintf(temp, "(*%s)", out);
+				else
+					sprintf(temp, "*%s", out);
+				strcpy(out, temp);
+			} else if (type == NAME) {
+				sprintf(temp, "%s %s", token, out);
+				out[0] = '\0'; /* rust sisters btfo */
+				strncat(out, temp, OUTLEN - 1);
+			} else {
+				err = 1;
+				printf("err: invalid input at %s\n", token);
+				while ((type = gettoken()) != '\n')
+					;
+				ungetch('\n');
+			}
+		}
+
+		if (!err)
+			printf("%s\n", out);
+	}
+
+	return 0;
+}