* k+ j9 o2 q( B( h代入以下代码,得:11,9,4,2,1,6 滑稽~
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' s2 _/ v/ U5 r; {5 f#include <iostream>, G( ^8 S5 h1 S M& {. U: ?
#include <string.h>
2 p- q: L" Y% Musing namespace std;
" f. g; S6 ], [% `template <class T>
# M3 U( L2 s+ u. O/ J4 m' i( u9 Sclass Node* Q9 S, q0 M- j7 l* S7 Q' w& g, ]
{
- t& i5 c" o b8 tpublic:, K4 K2 k' s5 q8 M: l0 _+ I" f
T data;- q: m4 `/ A" d [/ u8 n' R* B
Node<T> *next;
$ L1 Z4 g0 K7 Z' }6 V: {6 j4 z Node()
: S# ?9 Z' x& S& l5 b {
( l% ^. ~, P# }0 a5 N: {+ f this->next = NULL;# x/ Z$ g7 S: K$ W" G1 _ ]2 U
}
. b" ?5 E4 s4 ~, u Node(T data,Node<T> *next=NULL)2 [) j& G( S* B5 M5 R
{
, y& L' B, ] r) {6 T7 k this->data = data;' w+ N! H; A/ y+ N
this->next = next;* L" B! F8 S( u: b+ e
}
9 _/ t7 H7 j0 x};
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1 j5 h; C( G0 j5 _. p0 i( s1 x( ?template <class T> S8 J" b! F) k" H* J
class LinkedStack
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private:9 j, E4 J4 B* v' @ z- N( B
Node<T> *top;% ]9 Y" w; i/ A# B1 Y
public:* f! A8 x8 ^. ]; o a0 E, o
LinkedStack();1 O! J2 l( s- D3 [2 P, M; ?& t
~LinkedStack();
+ B- N0 b [6 }' q bool isEmpty();
5 @" R* B) ^5 s& V! f& ^ void push(T x);6 e) P) v4 w" D/ w
T pop();1 d5 O6 n, g; P' L$ J: @2 C
T get();! ]. _, ]: Y; \$ I: N, G9 v- E
};# C% ~ _$ J7 p0 d8 F9 ^- T
$ v( c# S5 Z4 U' Z8 d! \* f9 Ntemplate <class T>" H1 n! `4 ?: {" g! }
LinkedStack<T>::LinkedStack()
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top = NULL;
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" c6 P: o! H$ h; ~template <class T>
9 N2 I/ n- F3 d8 SLinkedStack<T>::~LinkedStack(), @, @0 _; b: }0 Q
{
- C# ]2 D5 t) p: u W b Node<T> *p = top;
" E$ a7 O4 Y7 g# z1 {1 G Node<T> *q;
+ x, {5 M0 F9 j- r! M; w2 l while(p!=top)2 E) v! F. W2 [6 J }8 d
{
" p& _, V* b0 r% Q/ M q = p;
: @- T# U! l+ m: o1 m( Y p = p->next;
( y& P. @% ~" C; S delete p;0 Q8 y. @6 A0 a/ y
}' V# q( g$ Y- @7 Q% f: e
top = NULL;
0 r8 ^/ _! C: p% g; Z& n( M}
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" i) k0 d4 e4 i: z# p4 }0 m1 K! Qtemplate <class T>. X Y W9 k0 G; u1 S
bool LinkedStack<T>::isEmpty()
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return top == NULL;
6 z9 N! \" I8 r7 ]4 B}
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template <class T>
( G" C" e, @) [' A& A4 F% @- f6 pvoid LinkedStack<T>::push(T x)
; i/ u: D; G4 P, N9 r! \{
" H# W6 a. A% K% y3 ^8 L top = new Node<T>(x,top);
$ k' d4 H) L: E) i5 B6 O}
4 N: W% A% }) R6 N, l- {' ?; u/ d
0 t) w" U0 A% J1 K0 c$ _$ T0 d! r1 ]template <class T>
5 b7 G8 ?8 ~9 X; r% _, ?. v1 GT LinkedStack<T>::pop()6 T# m: z' o) {
{" z1 q" ] f4 a# C4 g4 i$ k. V% d
if(!isEmpty())
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T x = top->data;
/ T' S# K" e) U: \; r+ ^& B: n Node<T> *p = top;; l) S2 k9 ^9 ^2 \
top = top->next;
1 K; S) T' x4 W7 d. T delete p;
. ?8 P1 K- f" m) R1 A# S$ d return x;. \8 Z8 \4 U* f
}7 B# s% _7 _6 q8 j
throw "空栈,不能执行出栈操作";
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template <class T>. X; y1 ~" E6 Z0 s+ I! ]: {) Y
T LinkedStack<T>::get()
6 H1 z% B# y7 Q! F1 z* W' M{
+ I9 G7 R! A9 L# v if(!isEmpty())
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return top->data;7 }- G" f8 P) w) H: e1 g+ e
}
) H# g. @* v" h+ _& B7 X' e& | throw "空栈,不能获得栈顶元素";
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6 }, K# T7 |* }; qchar * toPostfix(char *expstr)7 c1 f9 C( x& [/ E
{
" R) w' F; g7 |) c$ J P& C3 E" z LinkedStack<char> stack;+ Y, C, K+ y& H) l7 `
char *postfix = new char[strlen(expstr)*2];4 [3 I/ l5 j$ |* ?
int i=0;
7 H; v) q3 ^7 R' v int j=0;
: [+ h9 ?9 s+ e! T2 r2 s char out ;2 \' H# d2 g$ V# T: m J, i9 b) ~
while(expstr!='\0')
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9 P' Q4 S: L* o" t- } switch(expstr)
, z# t7 L+ v! f" }6 N {# ]) S: @2 I. Z9 Z& i R" @$ k, G$ k# w
case'+':
" ~" G7 v8 A% i* \5 c* b case'-':7 [( Q, x# U7 v1 w
while(!stack.isEmpty()&&stack.get()!='(')4 y8 E* `5 m' n5 W& w
{
2 f0 T5 Q# j1 m3 W1 O7 [ postfix[j++] = stack.pop();8 M: j# r( Z/ D7 Y' |
}# R" @5 F% L( d: {. H
stack.push(expstr[i++]);
% k& Q& ?8 ], O4 F break;! a1 d2 D* B! j% H7 r
case'*':+ n3 B: x9 l7 `) `2 h0 W
case'/':' s$ S3 X* F. B0 o' V% q9 i# g/ t
while(!stack.isEmpty()&&(stack.get()=='*'||stack.get()=='/'))
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postfix[j++] = stack.pop();
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stack.push(expstr[i++]);6 @6 [- L9 @' k$ q8 w7 ? p* [7 ]
break;8 ?; A; b' h2 u* @8 o$ d
case'(':stack.push(expstr[i++]);3 M1 I) g. [+ l; h4 W, j8 w
break;, r' S9 l# `* }" B, G' B
case')':out = stack.pop();- U8 R0 d7 v; w( R8 u/ [
while(!stack.isEmpty()&&out!='(')8 e0 `5 f: c9 _) M9 e T
{9 D9 v* G/ \' m/ Y4 S8 `- v
postfix[j++] = out;! t. n: S/ X& |; X+ V
out = stack.pop();
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break;2 j3 c" h& i+ p. Q3 t
default:. H$ ?9 S: F% m4 Y# w9 q; M
while(expstr>='0'&&expstr<='9'&&expstr!='\0')& Z& x1 x c) l
{) D, L- a3 P! g8 `
postfix[j++] = expstr[i++];8 d, |1 p+ F* e6 C' e
}
6 z( Z" Z! s! Z$ o0 n1 l postfix[j++]=' ';
' Q, a! q* \6 y) Y break;( W, _2 ~) { o( F
}
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0 m8 [0 D$ C. ~4 v/ Z- I6 W while(!stack.isEmpty())& d8 q9 ^% R8 [! u
{
1 C6 {0 ?2 n; B) J$ N3 g postfix[j++]=stack.pop();
8 f! c1 A; b2 ~+ z }
7 ~7 X. l$ q; `0 V, @4 Y/ S1 _ postfix[j]='\0';8 W) T: X3 \# P$ k
return postfix;9 y) F+ E+ d1 J, ~" {" g
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int value(char *postfix)4 s$ B5 Q3 q8 x5 s% Y( `5 P
{, L( f7 w7 I% D0 x C
LinkedStack<int> stack;
) a% Y5 m4 }0 P int i=0;1 a& G4 Y7 K$ j7 y
int result = 0;/ }9 c# y, K; _: a; q
while(postfix!='\0')
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if(postfix>='0'&&postfix<='9')" {. _+ ~' v/ l1 c" C, O
{
7 j- \* n6 y; S9 e) @9 l result = 0;
4 p2 R7 e' z! |+ d7 E7 d2 S: ~ while(postfix!=' ')
9 N1 k: p3 h% I6 _0 e {( N8 ~6 D% U/ N8 [! r* `* }, Y
result = result*10+postfix[i++]-'0';# d0 M% F* n3 k( Y0 J( h
}( v3 J F1 C' o8 q
i++; y# x$ S3 u. l9 T; {
stack.push(result);
4 e0 `( h( B: n4 _% ` }
0 l! E, Y# F% w. X! ?+ t else
& c! c( ]! i) |" d6 I/ h9 |5 K' k {
* N8 r6 r& z e1 c+ ?. A& C if(postfix!=' ')
2 h5 ?, }$ N* f0 {- @ {
+ H+ n6 P y" O" E int y = stack.pop();
$ p8 [! i. D* x% y int x = stack.pop();
1 j, f8 I X: O' X% P, R switch(postfix)
{% X; S0 x" u: q- [ {( V0 S% R! Z5 \$ c. w
case'+':result = x + y;
& H" i; n" n+ p break;
2 y9 Q9 Q n, X, U case'-':result = x - y;2 R9 F! A- ]1 I- f! i1 I
break;# F. e( W4 l- U, W; H7 U+ o/ o
case'*':result = x *y;
& S5 x8 m, m/ X6 G break;1 ~7 f- p$ q- M8 u
case'/':result = x / y;' u7 r7 H6 L* |
break;
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* a2 Z) S( L, L/ ^ stack.push(result);/ ?- R- T* K8 A# i ^) U
}! A! z5 S# U- }9 K
i++;
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}
- x/ g' ]4 a( j' ?+ {3 ^* r return stack.pop();# W0 [! d) Z; A: z" f! F) ]1 j
}
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0 ~/ {2 v* G8 p& ~3 ?. Nint main()
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//char *expstr = "121+10*(52-49+20)/((35-25)*2+10)";+ x* }' E9 }- g0 z* I
cout << "请输入表达式:";: h- f1 J1 S6 |6 }8 J
//char *a ;
8 V2 g0 Z5 k% x0 t2 G: d$ t3 p //cin >> *a;) K# K$ C8 f( y7 u/ x" i Z" A/ i" L! g; Q
char expstr[20]={0};5 P4 K5 M9 n& ]( u/ c U, u
while(1)" S8 R/ |( r0 [1 o! U( N6 E8 T
{3 ~. P8 Z: s0 ~- o/ k
cin>>expstr;
( k2 g5 J' s$ Y0 y! f1 N/ m char *postfix = toPostfix(expstr);
3 x; W( {1 e1 C* P; Z2 p cout << "expstr= "<<expstr << endl;4 ]" o& _6 ~1 ]+ Z @
cout << "postfix= "<<postfix<<endl;8 I( d1 \+ M% B- z9 N M+ Y S x
cout << "value= "<<value(postfix) << endl;
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return 0;
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