0 V3 {- k2 I/ r+ e( v8 u, Y; N代入以下代码,得:11,9,4,2,1,6 滑稽~& j |& s6 H' |: Y
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#include <iostream>
' u: \; t) b- H7 L% o5 S$ F#include <string.h>
8 Q1 m n/ j) G7 Kusing namespace std;9 K5 Q# O& x7 u, b3 Z* c
template <class T>3 Z' D3 }' h8 X6 z7 y$ ]# d
class Node) H" _, e9 v. a3 m3 i' d+ @' r
{) G: K/ u# @, w5 v5 [
public:
5 I# M3 E5 v" o) | T data; t6 ]# D6 [2 _7 j: Y; d8 R) K
Node<T> *next;2 F0 P1 f5 {7 q |, Q" Q$ { B3 D
Node()
3 Y. v+ g( U; C: }+ r {
% q7 g- s ^/ G, O7 |/ f# [, D this->next = NULL;- M" W& P ]8 ]4 U. q
}
- u& }; t( p# S0 Z* G- r Node(T data,Node<T> *next=NULL)
7 `* R; _$ B% u: o* z5 w {
9 S$ @) k2 a0 Z; i this->data = data;
$ s( v% l* H2 ?" j; O) [# Z. x6 V this->next = next;
+ [4 Y( I( b' v9 b# V* S. `1 \/ S }- k( d! P" P2 X
};1 }/ Z/ y! j. [- u
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template <class T>
7 q" [ w* U2 B2 S1 j! ~$ l" jclass LinkedStack9 v- q m( V7 _3 _' P( d. q
{" I6 u+ W' ]5 i. L y
private:
1 z! V6 p( E) b1 i; U' d! P! E Node<T> *top;
- H/ Q0 T [5 Tpublic:
5 d0 r' f5 B4 a A% O LinkedStack();( @9 L1 X0 O/ |4 j+ l2 [, Q/ X
~LinkedStack();0 _/ W* a& }. D. j# X' G2 U
bool isEmpty();0 T# L# o" A) Q: P' S% `
void push(T x);
7 s7 Y$ r8 O" i5 I; S { T pop();* h( S2 P9 Q; w
T get();: c, w* k; _0 v/ a0 }
};$ W) ~. P' A! H! ~! O7 i/ [
6 K* A8 N0 l; W% Q0 ?7 ^2 ^template <class T>. G- H. y, s/ z
LinkedStack<T>::LinkedStack()1 O' F8 W2 N z" u" q v$ |
{
( k8 x' W, ?+ h0 |/ |: [ top = NULL;! t& u6 T- [$ I2 D; p1 U4 K9 m0 d
}
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% j9 r' _ z0 V! ^" h. p: @2 r! dtemplate <class T>6 @8 \) _ K9 j. Q' D5 m7 ]" f
LinkedStack<T>::~LinkedStack()
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Node<T> *p = top;
Q( m' [5 g+ H Node<T> *q;
$ F) g2 J8 B: H8 N$ H while(p!=top)
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q = p;
" e0 _% w/ l9 m; a+ U p = p->next;
: G7 {% G) k1 Q" P delete p;
+ ^% K: C1 i# V }
& c, y8 v8 j! O: i% z/ v$ q) S# V top = NULL;
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template <class T>1 C7 c; X/ ~+ n$ A: Z' Z7 G' u5 |
bool LinkedStack<T>::isEmpty()
' b5 S" Q: w4 Z{
2 P' |* i, }1 J return top == NULL;2 q7 ^3 B$ t( @" T M& O! H7 y" j
}
; n* ~9 u9 e2 L
% c$ i6 U% t9 [ K Rtemplate <class T>
- c# o! j* K) mvoid LinkedStack<T>::push(T x)1 Q7 `0 V9 v8 M
{' U, f$ U& K. Z# O' l8 C
top = new Node<T>(x,top);9 \6 K+ L( p7 M ?" Y# r
}
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4 C$ o1 k( s- u: J5 N0 stemplate <class T>5 V* G& c0 q& m- J6 B
T LinkedStack<T>::pop()/ ]3 N, k# `; _* n% c7 A
{# }" F0 c3 I% A6 o3 _' F
if(!isEmpty())
\- t; t+ b6 G2 v4 u" w; | {
3 ~/ h/ o7 F! B& M T x = top->data;) g) ^1 I$ O/ {
Node<T> *p = top;% G0 ?7 m; i% V5 d K! x; R
top = top->next;& G6 _% T/ U3 }6 J; a3 [
delete p;) g: a* W! F1 ]8 b
return x;
! y( j8 {+ q: _% [4 }: e/ `3 h7 E+ v }: o- _: c$ _5 v$ O# ?, s; I
throw "空栈,不能执行出栈操作";
+ G; d" y! w7 |% \6 I( R}3 H' V" T* W3 E; G
0 a3 X# y" e# ]( S, gtemplate <class T>
# r2 g$ ]) x4 d* o0 \' ~: O) y$ H! zT LinkedStack<T>::get()* U' ~3 r' A$ z- A- \3 y. y- k
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if(!isEmpty()); v9 O/ e* l* @" C1 j
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return top->data;
, m1 Q' B! n8 N }
: h, g% L2 _# X throw "空栈,不能获得栈顶元素";( c) h8 t0 H: |
}
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char * toPostfix(char *expstr) T. t7 O p1 `. C
{
1 T |: m$ n( f. \ LinkedStack<char> stack;
% T: @% B' T8 x/ D: o7 k/ l8 p char *postfix = new char[strlen(expstr)*2];6 f9 N. C9 h a$ T0 K/ Z
int i=0; x; n* j$ u0 W, f o
int j=0;& Q$ Z; U0 p) N& P4 K6 { J
char out ;
9 ~8 e0 T) k) @* ` f. M/ @ while(expstr!='\0')$ A- e( @. u: M9 K" ]; u+ e! K$ c J9 B" }
{, w4 \/ F9 b4 `
switch(expstr)9 A8 ?) k& \3 C3 d
{
8 J+ r7 Q7 x+ D4 K case'+':
$ }, p7 D7 C/ X case'-':
j. z) o- r2 g: o4 J) u" E while(!stack.isEmpty()&&stack.get()!='(')% }( W0 ~( ^0 B8 j' _. x
{- P# \: @0 V- Z" {
postfix[j++] = stack.pop();
4 t) q, I- I" ]' U! T& | }
9 n$ Q' K* n+ @( i. \1 d/ o stack.push(expstr[i++]);! p! n6 }& n8 @& j0 x' y8 c
break;3 y! i! f' z. g3 k
case'*':6 ?2 }8 N( I* M ^: x0 L
case'/':- a% K& N8 x$ V0 h a* N5 x
while(!stack.isEmpty()&&(stack.get()=='*'||stack.get()=='/'))
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postfix[j++] = stack.pop();
6 w7 U7 X; R) _% q" n) x }
+ o- F# ?3 F0 _: v/ j, \2 }. R stack.push(expstr[i++]);5 r& S! C% q! K4 ~) G
break;' P/ J, ^: g: R! G
case'(':stack.push(expstr[i++]);
! l2 ~8 A1 J5 [0 } break;
, q) c" @. T) H- H9 i3 W* u case')':out = stack.pop();: Q) h4 Y3 L3 A8 B8 M6 U
while(!stack.isEmpty()&&out!='(')7 D* C# h, O$ u4 z, _
{
. E. q! j* z v) G; v, B! i postfix[j++] = out;
) R& \' F! p" C& ~' S+ l out = stack.pop(); U9 \, q. j+ }6 j
}5 c" U+ E7 c8 z$ _5 F
i++;0 Y7 [2 C4 @0 D0 m6 p
break;1 l2 D) l9 u1 m6 N# X& ?/ H
default:' z( D7 a1 q% v2 o
while(expstr>='0'&&expstr<='9'&&expstr!='\0')' N. Y9 J x9 [
{
4 m1 [7 P3 m/ }3 L& z postfix[j++] = expstr[i++];, `' D! [4 Q- |, v
}" B. G$ ~5 o. o: W4 Y i; Y1 Q( F: h
postfix[j++]=' ';4 j. u" R2 Q4 U
break;& L- G2 G3 z2 d/ g
}
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while(!stack.isEmpty())1 V& d+ J0 l& v0 Y2 q% g, B0 N
{
3 W/ a, B! w y3 K postfix[j++]=stack.pop();. L& D% z# p& V* G
}9 }+ E- i6 x) y; X1 j
postfix[j]='\0';- U9 @) W: |4 I: R. H
return postfix;; x2 C7 h" C0 y- p! T& {
}
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) D+ f% X8 s: x, ~& Z. dint value(char *postfix)2 f2 J' k6 a3 j$ W
{, P/ C6 C7 A3 A; s& V: A
LinkedStack<int> stack;
+ Z* d5 r' ?/ {, M- C/ ? int i=0;- z2 h+ n2 ^ F* G8 ~: Z
int result = 0;
& u: C4 K1 m" Y6 ? while(postfix!='\0')
6 ~% t- ` K# t4 \" @3 f {
. ?! B! ]4 K- J3 X' ?3 W0 U4 k2 e if(postfix>='0'&&postfix<='9')* o, @" `. w2 `+ b* O
{
5 X8 P) H7 g8 a result = 0;
0 x, G. x$ `- X8 h; I( L0 ] while(postfix!=' ')
5 w4 {7 i* L9 {( b v6 v {. E ^# v+ w( k. a: k
result = result*10+postfix[i++]-'0';
2 y: Z2 Z }; F6 _# K }
6 I8 V( Y. J( W3 k! B1 `6 y- \ i++;
* H4 ^3 u' t- O& Q( V stack.push(result);/ q: q" W! l4 N* _
}1 j' {1 Q' _9 l# s: G( f' s
else
8 e" A$ p9 h! I" n$ l Q1 K3 N& C {
" r/ }+ _: `% R! n4 ?$ | if(postfix!=' ')9 y( Q( M, F" ?( t) X
{
3 P. k. v7 e; s int y = stack.pop();' M* B' L4 ~- v
int x = stack.pop();0 e: N8 y3 {0 R3 b0 }/ l1 O' {
switch(postfix)) x1 ?; A' b4 Y6 a$ p9 j# U
{9 w- s( g, m. m2 }# h, u' w0 p
case'+':result = x + y;
7 V9 {3 B" {, D/ L8 Y. A break;; S: G3 i: z5 a. s, f& g
case'-':result = x - y;
% k2 t7 F: L8 m% ]2 q8 L9 W break;
- D$ T+ @' U6 u- P, ~, ] case'*':result = x *y;
* N9 U* M+ K( m, d0 x break;# `2 N& d( a) h) T
case'/':result = x / y;
9 Z$ b8 w% q* } break;
+ m* {! q# n9 j9 n }, w* ]" _: r4 Y! s& V* \ [. k: r2 w
stack.push(result);
" q$ _% B! v0 W$ O1 ~/ P$ W }
% O3 v# O# g) O" d i++;
: w% @9 ?% m7 a0 [ }8 ?/ L1 i( L F0 L% M8 {% \$ j
}
; N3 G7 j3 j2 X return stack.pop();: b- k: P. }) t' k2 m& _
}
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2 v9 b. z# d& ?2 g3 D1 b8 Pint main()/ d4 @3 P3 n3 H6 t9 I
{* i' Q; @! P) a, [, A/ w
//char *expstr = "121+10*(52-49+20)/((35-25)*2+10)";
3 \) `. Z) z7 k1 U- J cout << "请输入表达式:";; S$ Z5 n/ q6 g4 Q8 n
//char *a ;) y1 n, C! ]( B, }, s! j. S. k( \ g
//cin >> *a; O0 A1 l. M8 U! N5 k1 s) J: _
char expstr[20]={0};8 \" p2 l* W( N: O$ {& e- I
while(1)1 e5 [% r1 k9 m6 H5 D' i
{- B$ }# R7 @) W0 s' \" C3 @% @
cin>>expstr;
- \7 w3 @/ | w4 u' Q6 W% c: u/ U. S char *postfix = toPostfix(expstr);7 y- H- D1 @% ^! F+ X( p$ l! o+ D
cout << "expstr= "<<expstr << endl;- M- B. {+ }' j! o# t
cout << "postfix= "<<postfix<<endl;, e2 `. U) r0 [+ E6 {
cout << "value= "<<value(postfix) << endl;
/ \0 A% }1 W/ G$ d; S) P, C& R }
) ?* q7 z9 k& j% E return 0;
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