解析和计算表达式,并以树状层次显示元素关系

1+2*3/7+123+(1+3*5) 1.如果遇到数据则加入左侧 2.如果遇到运算符,优先级较高,入左侧,先入数,然后在其右侧入运算符 如果优先级较低或相等,或者栈空,则入右侧 3.遇到括号,则入左侧 4.在栈中记录当前节点的位置 符号入栈时,同时将运算符保存 如: 2+3*(5+7)+8 过程如下: 1.取得数据2,入栈, 2.取运算符+,由于栈空,入栈,写入树当前节点的左侧,和数据一起,先入数据 3.取得数据3,入栈 4.取得运算符*,优先级较高,入栈,同时将数据和此运算符写入树当前节点左侧 5.取得运算符(,优先级较高,入栈,下一节点将是当前节点的左节点,设置标志 6.取得数据5,入栈 7.取得运算符+,优先级较高,入栈,置于当前节点左侧 8.取得数据7,入栈 9.取得运算符),优先级较低,将数据写入当前节点右侧 出栈,直到遇到(,当前节点切换到运算符栈顶所指节点 10.取得运算符,优先级较低,同时上一个非数据, 则出栈,直到运算符优先级变得较高,当前节点切换到最后出栈的运算符的位置 将当前运算符置于右侧, 11.取得数据,入栈 12.取得结束符,优先级最低,将数据写入当前节点右侧 出栈,直到运算符优先级变得较高, 当前节点切换到最后出栈的运算符的位置 以栈顶的运算符表示当前位置 当后面得运算符较低时,可能会出空栈,则当前节点位置由最后一个元素确定 如果栈空,则以最后出栈的运算符节点作为当前位置 如果上一个为运算符或者为空,同时这一个为单目运算符,则表示对下一个数的计算 如果上一个为数据,而运算符置于左侧,则一般数据放在运算符之前 对于:－２ 取得运算符-,因为没有数据表示对下一个数计算, 将运算符直接入栈,并将下一节点置入左侧, 通常单目运算符优先级最高,相邻的两个单目运算符后者比前者高 2004年10月16日 11:25:09 abc := fun1(2 + 3, 4 * 5); // 词法分析结果 abc otAssign:-20 otFun:-380 2 otAdd:-1 3 otNext:60 4 otMul:-160 5 otRight:1 otEnd:20 // 表达式语法分析 Push Data-1-V:abc Data:abc Oper: Buff:abc Push Oper-2:otAssign Data:abc Oper:otAssign Buff:abc-1,otAssign Push Oper-2:otFun Data:abc Oper:otAssign,otFun Buff:abc-R1,otAssign-L2,otFun Push Data-6:2 Data:abc,2 Oper:otAssign,otFun Buff:abc-R1,otAssign-L2,otFun,2 Push Oper-2:otAdd Data:abc,2 Oper:otAssign,otFun,otAdd Buff:abc-R1,otAssign-L2,otFun-L3,2-R4,otAdd Push Data-6:3 Data:abc,2,3 Oper:otAssign,otFun,otAdd Buff:abc-R1,otAssign-L2,otFun-L3,2-R4,otAdd-R5,3 Pop Data-3:3 Data:abc,2 Oper:otAssign,otFun,otAdd Buff:abc-R1,otAssign-L2,otFun-L3,2-R4,otAdd-R5,3 Pop Oper-5:otAdd Data:abc,2 Oper:otAssign,otFun Buff:abc-R1,otAssign-L2,otFun-L3,2-R4,otAdd-R5,3 Push Oper-5:otNext Data:abc,2 Oper:otAssign,otFun,otNext Buff:abc-R1,otAssign-L2,otFun-L3-R6,2-R4,otAdd-R5,3,otNext Push Data-6:4 Data:abc,2,4 Oper:otAssign,otFun,otNext Buff:abc-R1,otAssign-L2,otFun-L3-R6,2-R4,otAdd-R5,3,otNext,4 Push Oper-2:otMul Data:abc,2,4 Oper:otAssign,otFun,otNext,otMul Buff:abc-R1,otAssign-L2,otFun-L3-R6,2-R4,otAdd-R5,3,otNext,4,otMul Push Data-6:5 Data:abc,2,4,5 Oper:otAssign,otFun,otNext,otMul Buff:abc-R1,otAssign-L2,otFun-L3-R6,2-R4,otAdd-R5,3,otNext-L6,4-R7,otMul-R8,5 Pop Data-3:5 Data:abc,2,4 Oper:otAssign,otFun,otNext,otMul Pop Oper-5:otMul Data:abc,2,4 Oper:otAssign,otFun,otNext Pop Data-3:4 Data:abc,2 Oper:otAssign,otFun,otNext Pop Oper-5:otNext Data:abc,2 Oper:otAssign,otFun Pop Data-3:2 Data:abc Oper:otAssign,otFun Pop Oper-3:otFun Data:abc Oper:otAssign Pop Data-3:abc Data: Oper:otAssign Pop Oper-5:otAssign Data: Oper: 2004年10月17日 11:22:01 Expr: abc := fun1(2 + 3, 4 * 5); 词法分析 Data: abc,Left: 0 Oper: otAssign:-20,Left: 0 Oper: otFun:-380,Left: 0 Data: 2,Left: 0 Oper: otAdd:-1,Left: 0 Data: 3,Left: 0 Oper: otNext:60,Left: 0 Data: 4,Left: 0 Oper: otMul:-1,Left: 0 Data: 5,Left: 0 Oper: otRight:1,Left: 0 Oper: otEnd:20,Left: 0 语法分析 Push_1 Data: abc,Left: 0 Push_2 Oper: otAssign:-20,Left: 0 Push_2 Oper: otFun:-400,Left: 0 Push_6 Data: 2,Left: 0 Push_2 Oper: otAdd:-100,Left: 0 Push_6 Data: 3,Left: 0 Pop__2 Data: 3,Left: 5 Pop__5 Oper: otAdd:-100,Left: 4 Set__1 Data: otAdd,Left: 4 Push_5 Oper: otNext:-40,Left: 6 Push_6 Data: 4,Left: 0 Push_2 Oper: otMul:-200,Left: 0 Push_6 Data: 5,Left: 0 Pop__2 Data: 5,Left: 9 Pop__5 Oper: otMul:-200,Left: 8 Set__1 Data: otMul,Left: 8 Pop__2 Data: otMul,Left: 8 Pop__5 Oper: otNext:-40,Left: 6 Set__1 Data: otNext,Left: 6 Pop__2 Data: otNext,Left: 6 Pop__3 Oper: otFun:-400,Left: 2 Pop__2 Data: abc,Left: 0 Pop__5 Oper: otAssign:-20,Left: 1 2004年10月17日 11:46:41 Push_1 Data: abc,Left: 0 Push_2 Oper: otAssign:-20,Left: 0 Push_2 Oper: otFun:-400,Left: 0 Push_6 Data: 2,Left: 0 Push_2 Oper: otAdd:-100,Left: 0 Push_6 Data: 3,Left: 0 Pop__2 Data: 3,Left: 5 Pop__5 Oper: otAdd:-100,Left: 4 Set__2 Data: otAdd,Left: 4 Push_5 Oper: otNext:-40,Left: 6 Push_6 Data: 4,Left: 0 Push_2 Oper: otMul:-200,Left: 0 Push_6 Data: 5,Left: 0 Pop__2 Data: 5,Left: 9 Pop__5 Oper: otMul:-200,Left: 8 Set__2 Data: otMul,Left: 8 Pop__2 Data: otMul,Left: 8 Pop__5 Oper: otNext:-40,Left: 6 Pop__2 Data: otAdd,Left: 4 Pop__3 Oper: otFun:-400,Left: 2 Call_1 Oper: otFun:-400,Left: 2 Set__1 Oper: otFun:-400,Left: 2 Pop__2 Oper: otFun:-400,Left: 2 Pop__5 Oper: otAssign:-20,Left: 1 Set__2 Data: otAssign,Left: 1 2004年10月17日 14:32:39 Oper: otFun:-400,Left: -1, Right: 0 Data: 1,Left: -1, Right: 1 Oper: otNext:-1,Left: -1, Right: 2 Data: 2,Left: -1, Right: 3 Oper: otRight:1,Left: -1, Right: 4 Push_2 Oper: otFun:-400,Left: -1, Right: 0 Push_6 Data: 1,Left: -1, Right: 1 Push_2 Oper: otNext:-40,Left: -1, Right: 2 Push_6 Data: 2,Left: -1, Right: 3 Pop__2 Data: 2,Left: -1, Right: 3 Pop__5 Oper: otNext:-40,Left: 1, Right: 2 Pop__2 Data: 1,Left: -1, Right: 1 Pop__3 Oper: otFun:-400,Left: 2, Right: 0 Call_1 Oper: otFun:-400,Left: 2, Right: 0 Set__1 Oper: otFun:-400,Left: 2, Right: 0 2004年10月17日 16:35:53 Data: Var: abc,Left: -1, Right: -1 Oper: otAssign:-20,Left: -1, Right: -1 Oper: otFun:-380,Left: -1, Right: -1 Data: 2,Left: -1, Right: -1 Oper: otAdd:-1,Left: -1, Right: -1 Data: 3,Left: -1, Right: -1 Oper: otNext:60,Left: -1, Right: -1 Data: 4,Left: -1, Right: -1 Oper: otMul:-1,Left: -1, Right: -1 Data: 5,Left: -1, Right: -1 Oper: otRight:1,Left: -1, Right: -1 Oper: otEnd:1,Left: -1, Right: -1 Push_1 Data: Var: abc,Left: -1, Right: -1 Push_2 Oper: otAssign:-20,Left: -1, Right: -1 Push_2 Oper: otFun:-400,Left: -1, Right: -1 Push_6 Data: 2,Left: -1, Right: -1 Push_2 Oper: otAdd:-100,Left: -1, Right: -1 Push_6 Data: 3,Left: -1, Right: -1 Pop__2 Data: 3,Left: -1, Right: -1 Pop__5 Oper: otAdd:-100,Left: 5, Right: -1 Set__2 Oper: otAdd:-100,Left: 5, Right: -1 Push_5 Oper: otNext:-40,Left: 4, Right: -1 Push_6 Data: 4,Left: -1, Right: -1 Push_2 Oper: otMul:-200,Left: -1, Right: -1 Push_6 Data: 5,Left: -1, Right: -1 Pop__2 Data: 5,Left: -1, Right: -1 Pop__5 Oper: otMul:-200,Left: 9, Right: -1 Set__2 Oper: otMul:-200,Left: 9, Right: -1 Pop__2 Oper: otMul:-200,Left: 9, Right: -1 Pop__5 Oper: otNext:-40,Left: 8, Right: -1 Pop__2 Oper: otAdd:-100,Left: 5, Right: -1 Pop__3 Oper: otFun:-400,Left: 6, Right: -1 Call_1 Oper: otFun:-400,Left: 6, Right: -1 Set__1 Oper: otFun:-400,Left: 4, Right: -1 Pop__2 Oper: otFun:-400,Left: 4, Right: -1 Pop__5 Oper: otAssign:-20,Left: 2, Right: -1 Set__2 Oper: otAssign:-20,Left: 2, Right: -1 2004年10月19日 8:29:29 abc := fun1(2 + 3, 4 * 5, 6 - 7); Data: 0: ,Left: 2, Right: -1 Data: 1: Var: abc,Left: -1, Right: -1 Oper: 2: otAssign,Left: 1, Right: 3 Oper: 3: otFun,fun1,Left: 5, Right: 7 Data: 4: 2,Left: -1, Right: -1 Oper: 5: otAdd,Left: 4, Right: 6 Data: 6: 3,Left: -1, Right: -1 Oper: 7: otNext,Left: 9, Right: 11 Data: 8: 4,Left: -1, Right: -1 Oper: 9: otMul,Left: 8, Right: 10 Data: 10: 5,Left: -1, Right: -1 Oper: 11: otNext,Left: 13, Right: -1 Data: 12: 6,Left: -1, Right: -1 Oper: 13: otSub,Left: 12, Right: 14 Data: 14: 7,Left: -1, Right: -1 Oper: 15: otRight,Left: -1, Right: -1 Oper: 16: otEnd,Left: -1, Right: -1 2004年10月19日 15:51:56 Root: [0] ,Left: 2,