6 H/ o- Z& Z, X; f; F代入以下代码,得:11,9,4,2,1,6 滑稽~# a% {+ @& U* u2 t: M7 ^
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#include <iostream>, O, ^" ^- H( L2 a
#include <string.h>+ e6 l, U5 D- V9 a# w* M
using namespace std;
+ H7 a% z' f J0 l( B) ?$ C8 Dtemplate <class T>* Y4 R8 Q, q+ `' d% y& Q9 d$ ]$ j
class Node' }4 d* |( A& q- ^+ E4 N+ @2 J
{
8 e/ T( V7 J% m! H9 Jpublic:% ], }) _" V0 g( ?# k3 Z
T data;7 i9 s/ `) N( C
Node<T> *next;
# S5 J. I9 b |% G7 C4 e Node()
S6 t9 ~6 X, D7 j; a( W7 D7 E {
" T+ H' e! j1 r, }/ S8 ~$ K, ^* }" o this->next = NULL;
8 s" m9 O# l5 [ }
( b( I( T/ G5 h Node(T data,Node<T> *next=NULL)
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this->data = data;; V* s+ h0 t& R3 f' h' d8 P: l
this->next = next;% H9 T* k' v T8 |3 V
} D b! |$ d3 l) m
};
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template <class T>2 b+ ]7 [) t. S; Q+ G z$ x
class LinkedStack- n$ E8 A7 Y! J) ]+ I9 \2 |, F
{
g; k. i. }' X7 R5 ]private:3 f4 N4 [ n" k/ q2 D
Node<T> *top;& p/ z6 Q3 V8 h! f4 L( K: d/ D
public:
( F0 X ]2 a+ C LinkedStack(); D! Y% S9 |* |$ O5 r5 z
~LinkedStack();
7 q% {; C8 N! l; M bool isEmpty();
! x7 p- K$ j1 f# ^ void push(T x);
) D& G2 H& i9 H) Y T pop();
6 Y/ K# d/ ]4 E0 C; s% C9 x T get();
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template <class T>( M J5 P( V; k& ]5 u0 F9 y, z
LinkedStack<T>::LinkedStack()
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top = NULL;
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template <class T>4 u. s- S* X5 X0 h
LinkedStack<T>::~LinkedStack()
+ @0 E; I. j- {% U4 [5 Z{
5 b+ o. Z) f* ]) t+ A% H+ ] Node<T> *p = top;
, U4 m5 h( Y: X1 Y0 S1 }, z' O Node<T> *q;
0 H; w- Q1 E' q0 F' z. g& ` V1 l while(p!=top)
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q = p;% l S! F) y" b! D% _+ N
p = p->next;
; a: b) F: y# B3 I: r/ E+ m delete p;
* }: I* B/ \( ~2 c& P }
0 P/ G4 d9 U7 S/ A9 {0 E( N/ W top = NULL;
9 K0 U) Y. i+ }5 I! |}
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Q/ Z( G$ l7 X3 n& V) j2 t& itemplate <class T>
: u% q+ l9 E5 k M+ ebool LinkedStack<T>::isEmpty()/ M* |8 H2 @: Y `
{
0 A/ l0 U* j1 w' g9 `: u' m return top == NULL;
7 J/ y$ A6 y/ K}
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template <class T>1 n M: }8 M+ C' j, t! R' Q8 s
void LinkedStack<T>::push(T x) x; ~9 ` p, a/ u! L
{
) b, P. ^, Q$ J" K4 X9 ], U) U top = new Node<T>(x,top);9 [0 y9 k6 s, h+ O
}
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/ e) }, M( U3 ~/ A: ~2 ?* g, c( Otemplate <class T>
% U& _" Q6 J( T& Q" k7 z: lT LinkedStack<T>::pop()
8 P6 O+ U/ W3 r4 m{
3 p5 g& b9 d9 V7 s, G8 B( ? if(!isEmpty())
2 N" {* L9 I% l a# q {
$ Y7 a! d7 l- l. g/ F! c0 l6 g5 Q T x = top->data;
, ~) G0 b1 ^8 }; Z6 Z Node<T> *p = top;& ]2 I! m+ J/ n: j; Y" w
top = top->next;# z1 H$ E( ]) Y6 P
delete p;9 Y" o/ U. m: e7 G4 Y; V
return x;
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. m( W# x& Y0 v: x$ V throw "空栈,不能执行出栈操作";
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template <class T>0 E6 z# |' Z5 H+ T2 x6 a) E8 h
T LinkedStack<T>::get(); h7 n+ Q( a) S% @
{
! I& n* q, U' G7 ~0 u; p: n$ y$ x( c if(!isEmpty())# c& ^2 T4 c5 [8 D9 _0 x$ r# U1 v
{6 p% }' i. W2 z. y& x9 d
return top->data;
" f' d2 h/ a5 Y: c }
) L: ?* w( l ]$ A/ Q& W throw "空栈,不能获得栈顶元素";9 T% J3 V4 {" {& ?( W F" v
}
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1 E' D. v6 v9 [7 a" s( echar * toPostfix(char *expstr)
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9 M7 E- A1 K$ l& d LinkedStack<char> stack;8 V% L; }2 n" k- [- x: @! N+ D
char *postfix = new char[strlen(expstr)*2];! r8 e, a2 B& r( ?! W! \# O. b7 H
int i=0;- f4 L& F: y W J/ ~+ U' W
int j=0;7 L$ V5 V+ f! @/ o, ?/ I( k
char out ;
5 \; z# F7 \7 p6 i0 ^0 T+ A while(expstr!='\0')
* q8 b' [1 Y" H. ] {
! A6 Y$ N- Z/ @* v switch(expstr)
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case'+':+ E" K$ l9 | T! r+ b
case'-':5 c; o) h0 ^( E j; `" B
while(!stack.isEmpty()&&stack.get()!='(')
4 F" @) A: @* |% o {
) W3 N7 ^! p0 @. p+ E, K" T postfix[j++] = stack.pop();
0 U( w$ J$ _; B }
& E7 c" O' r: R stack.push(expstr[i++]);8 m2 A, @. J: W8 ^* _9 q
break;
5 ^- N1 Y' j" l5 L; y7 M3 z# ~, N case'*':3 ~5 e, c' \! P4 z5 t* ]) [( `: t/ }
case'/':! `- L4 W2 B. w" u$ \0 ^4 I6 G, `
while(!stack.isEmpty()&&(stack.get()=='*'||stack.get()=='/'))& k6 U; N: y; [
{2 Z( a$ m m; v5 N$ W7 ?
postfix[j++] = stack.pop();5 }& ^; \6 q4 t+ L- w6 U
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stack.push(expstr[i++]);
# J3 l$ D! Q5 P% h7 }2 X% c8 X break;
' C5 b% a) m; k3 M case'(':stack.push(expstr[i++]);( D# h6 K9 N# _: K
break;
* P+ U5 C1 n0 ? case')':out = stack.pop();
# b$ D" t4 Y- O, B1 i+ W while(!stack.isEmpty()&&out!='(')
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postfix[j++] = out;! \5 O. N% E7 ?7 \) R
out = stack.pop();
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i++;. k9 V, I/ R. f/ X' J: F
break;( T7 ^$ q! n* v
default:6 {: P; y% u; T' V
while(expstr>='0'&&expstr<='9'&&expstr!='\0')
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postfix[j++] = expstr[i++];( E3 f0 @3 R- b+ S; F. d! d
}
) q9 a: }$ a# V3 M& w, V5 t postfix[j++]=' ';
' i0 n( L* n7 ?4 X break;4 t: {( R0 R) s( o* g8 R
}
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# V* v0 S7 J! ?0 p while(!stack.isEmpty())) F+ F' ~; M- ^7 Y& C3 x
{
% u0 C4 d* [ r" W postfix[j++]=stack.pop();7 A$ Y; h) g3 r/ @8 E
}$ i* H$ f; J- E \6 }
postfix[j]='\0';7 p7 B. Y0 ?5 ^1 n
return postfix;
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int value(char *postfix)% w8 s9 o. H% V5 U2 C5 X1 h' R
{
+ |5 M8 b5 a( c LinkedStack<int> stack;+ z* J2 c7 d% J) W D
int i=0;1 s7 w4 M. r0 d: Y% X3 s
int result = 0;
% K6 C, i3 v7 {! Q7 H' g while(postfix!='\0')
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if(postfix>='0'&&postfix<='9')- }' s; u) F G( T
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result = 0;4 e' H7 j/ R. L
while(postfix!=' ')/ @7 {/ J0 N( Q$ L/ v
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result = result*10+postfix[i++]-'0';6 A9 W: M, \4 Y# B+ N: {2 R
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i++;
0 ?' |# e |8 Q. |6 p, ? stack.push(result);
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" t7 ~& N7 p+ s0 ~ else, o |5 h1 h7 W! V% D! x
{
; h6 b" O# @9 h! ?( U* v: L if(postfix!=' ')
3 H: b: h4 k7 b5 l {
) v0 a6 Y7 m$ q* f/ h! Z: ]1 ] int y = stack.pop(); u( b- G- r2 ?8 e( B
int x = stack.pop();
! W N2 M/ W/ e7 U! s: Z- o7 k0 K switch(postfix)7 z+ l7 B; d, B8 \2 _5 R7 f
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case'+':result = x + y;9 O* Y2 v8 C+ K! h7 p7 e
break;
$ t+ z. l" a$ c$ _0 @6 K; I5 | case'-':result = x - y;
; U. |5 a( }1 \, L6 { break;
9 O9 x: D" z5 N! Q case'*':result = x *y;) o0 [( ]0 h3 u H% N& R
break;/ l; h% m8 |: A$ o6 Z
case'/':result = x / y;
/ d) X, G3 ~% Q% v2 B6 q& F break;
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stack.push(result);
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i++;& l2 H* m9 R3 d
}
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8 S6 g' o. y8 _+ n return stack.pop();
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1 a3 L: ~+ }$ q; R0 Nint main()! `5 _* Z' `( ?
{
/ A- n4 Q8 F) X2 r' K i //char *expstr = "121+10*(52-49+20)/((35-25)*2+10)";
, _& N( A# f" i/ t cout << "请输入表达式:";8 b; a) K( P# F: ]( U4 Y7 c
//char *a ;
0 C2 V; V8 l' G) e O //cin >> *a;; {0 ]+ \5 Z% A- |! d7 E4 L. d
char expstr[20]={0};
0 j3 a; O7 b# f: V while(1)0 g+ ^6 i" K0 R5 R D6 I( B
{
. p1 ~& T' h3 c9 l' C( h4 C cin>>expstr;
! }* H w; O* z I8 v2 s char *postfix = toPostfix(expstr);+ ~, ]* ?3 `9 K, p' `! W
cout << "expstr= "<<expstr << endl;0 ?$ w* n Q8 z m
cout << "postfix= "<<postfix<<endl;0 j% S Z5 O9 d& P
cout << "value= "<<value(postfix) << endl;" d% r8 u0 e5 B* V* _9 _& X
}
2 ?4 b/ I3 g: B return 0;2 C6 e; \* w- m, B8 L
} |