listing.txt

完成一个简化的C语言编译程序

	1:resverved word:int
	1:ID, name=gcd
	1:(
	1:resverved word:int
	1:ID, name=u
	1:,
	1:resverved word:int
	1:ID, name=v
	1:)
	2:{
	3:resverved word:if
	3:(
	3:ID, name=v
	3:==
	3:NUM, val= 0
	3:)
	3:resverved word:return
	3:ID, name=u
	3:;
	4:resverved word:else
	4:resverved word:return
	4:ID, name=gcd
	4:(
	4:ID, name=v
	4:,
	4:ID, name=u
	4:-
	4:ID, name=u
	4:/
	4:ID, name=v
	4:*
	4:ID, name=v
	4:)
	4:;
	5:}
	7:resverved word:int
	7:ID, name=main
	7:(
	7:)
	8:{
	9:resverved word:int
	9:ID, name=x
	9:;
	10:resverved word:int
	10:ID, name=y
	10:;
	11:resverved word:int
	11:ID, name=result
	11:;
	12:ID, name=x
	12:=
	12:NUM, val= 49
	12:;
	13:ID, name=y
	13:=
	13:NUM, val= 21
	13:;
	14:ID, name=result
	14:=
	14:ID, name=gcd
	14:(
	14:ID, name=x
	14:,
	14:ID, name=y
	14:)
	14:;
	15:resverved word:return
	15:ID, name=result
	15:;
	16:}
	17:EOF

Syntax tree:
   ReturnType 1 Declaration FuncVar: gcd 
    Declaration SingleVar:u 
    Declaration SingleVar:v 
    Compound 
      If 
        Op:  ==
          Id: v 
          const: 0 
        Return
          Id: u 
        Return
          Call:gcd 
            Id: v 
            Op:  -
              Id: u 
              Op:  *
                Op:  /
                  Id: u 
                  Id: v 
                Id: v 
   ReturnType 1 Declaration FuncVar: main 
    Compound 
      Declaration SingleVar:x 
      Declaration SingleVar:y 
      Declaration SingleVar:result 
      AssignStmt 
        Id: x 
        const: 49 
      AssignStmt 
        Id: y 
        const: 21 
      AssignStmt 
        Id: result 
        Call:gcd 
          Id: x 
          Id: y 
      Return
        Id: result 

Building Symbol Table ...
Variable Name Location Line Numbers Type
-----------------------------------

---layerno: 1
gcd            0            5    1
u              0            1    1
v              1            1    1
main           1           16    1

---layerno: 2

x              2            9    1
y              3           10    1
result         4           11    1

Checking Types ...

Type Checking Finished