4 files changed, 107 insertions, 0 deletions
diff --git a/sem1/osc/mm11/opgaver.md b/sem1/osc/mm11/opgaver.md
index 8fab5c4..276236a 100644
--- a/sem1/osc/mm11/opgaver.md
+++ b/sem1/osc/mm11/opgaver.md
@@ -26,3 +26,7 @@ Denne laver jeg måske senere.
 
 Denne er løst i regn mappen. 
 Kør `make run` deri for at køre.
+
+# Opgave 4
+
+I regn2 mappen
diff --git a/sem1/osc/mm11/regn2/Makefile b/sem1/osc/mm11/regn2/Makefile
new file mode 100644
index 0000000..9640aaa
--- /dev/null
+++ b/sem1/osc/mm11/regn2/Makefile
@@ -0,0 +1,30 @@
+
+LEX=flex
+YACC=bison
+LIBS=-ly -lfl -lm
+CC=gcc
+
+PROG=regn
+TRASH=lex.yy.c $(PROG).tab.c $(PROG) $(PROG).tab.h $(PROG).output
+
+$(PROG): $(PROG).tab.o lex.yy.o
+		$(CC) -o $@ $^ $(LIBS) 
+
+$(PROG).tab.c $(PROG).tab.h: $(PROG).y
+		$(YACC) -d -v $(PROG).y
+
+lex.yy.c: $(PROG).l
+		$(LEX) $(PROG).l
+
+%.o: %.c
+	$(CC) -c -o $@ $^
+
+PHONY: clean run
+
+run: $(PROG)
+	./$(PROG)
+
+clean:
+	rm -f *.o
+	rm -f $(TRASH)
+
diff --git a/sem1/osc/mm11/regn2/regn.l b/sem1/osc/mm11/regn2/regn.l
new file mode 100644
index 0000000..9988ddd
--- /dev/null
+++ b/sem1/osc/mm11/regn2/regn.l
@@ -0,0 +1,27 @@
+%{
+#include <math.h>
+#include <string.h>
+#include "regn.tab.h"
+%}
+
+realtal      ([0-9]+|([0-9]*\.[0-9]+))([eE][-+]?[0-9]+)?
+op_log		 log
+op_exp		 exp
+op_sqrt		 sqrt
+
+%%
+{realtal}      {yylval.dval = atof(yytext); 
+                return TAL;}
+{op_log}	   {return LOG;}
+{op_exp}	   {return EXP;}
+{op_sqrt}	   {return SQRT;}
+
+[ \t] ;
+
+
+'$'            {return 0;} 
+
+\n|.           {return yytext[0];} 
+
+%%
+
diff --git a/sem1/osc/mm11/regn2/regn.y b/sem1/osc/mm11/regn2/regn.y
new file mode 100644
index 0000000..a181cb3
--- /dev/null
+++ b/sem1/osc/mm11/regn2/regn.y
@@ -0,0 +1,46 @@
+%{
+#include <stdio.h>
+#include <math.h>
+#include <string.h>
+%}
+
+%union {
+	double          dval;
+}
+
+%token <dval> TAL
+%token LOG EXP SQRT
+
+%left '-' '+'
+%left LOG EXP SQRT
+%left '*' '/'
+%right UMINUS
+
+%type <dval> expression
+
+%%
+
+statement_list: statement '\n'
+	  | statement_list statement '\n' ;
+
+statement:  expression					{;};
+
+expression: expression '+' expression   {printf("sum \n");}
+	  | expression '-' expression		{printf("sub \n");}
+	  | expression '*' expression		{printf("mul \n");}
+	  | expression '/' expression		{if ($3 == 0.0) 
+                                           yyerror("divide dy zero");
+                                         else printf("div \n");}
+	  | '-' expression %prec UMINUS		{printf("neg \n");}
+	  | '(' expression ')'				{;}
+	  | LOG expression					{printf("log \n");}
+	  | EXP expression					{printf("exp \n");}
+	  | SQRT expression					{printf("sqrt \n");}
+          | TAL                         {printf("load %f \n", $$);};
+%%
+
+int main()
+{ 
+  yyparse(); 
+}
+