4.out

pl0

   0  var a,b;
   1  begin
   2      a:=25;
   4      if a=1 then b:=2 else b:=3;
  13      write(a,b)
  17  end.
   1   INT	0	5
   2   LIT	0	25
   3   STO	0	3
   4   LOD	0	3
   5   LIT	0	1
   6   OPR	0	8
   7   JPC	0	11
   8   LIT	0	2
   9   STO	0	4
  10   JMP	0	13
  11   LIT	0	3
  12   STO	0	4
  13   LOD	0	3
  14   WRT	0	0
  15   LOD	0	4
  16   WRT	0	0
  17   OPR	0	0
   0   JMP	0	1
   1   INT	0	5
   2   LIT	0	25
   3   STO	0	3
   4   LOD	0	3
   5   LIT	0	1
   6   OPR	0	8
   7   JPC	0	11
   8   LIT	0	2
   9   STO	0	4
  10   JMP	0	13
  11   LIT	0	3
  12   STO	0	4
  13   LOD	0	3
  14   WRT	0	0
  15   LOD	0	4
  16   WRT	0	0
  17   OPR	0	0

开始执行PL/0程序:
25
3
输出:25
输出:3
PL/0程序运行结束!