/ z9 v4 d1 p+ J9 }* G, T3 v代入以下代码,得:11,9,4,2,1,6 滑稽~9 T/ A- u, H9 h- S% c
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#include <iostream>
2 _& q4 f; W3 C$ A2 Q3 ]#include <string.h>
/ z' {9 M3 K1 q- w- e$ d4 `, Ousing namespace std;
7 g+ R9 V5 o1 M. U" R4 o6 ttemplate <class T>! z3 _2 t- q z9 N6 N4 }
class Node
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public:4 @- v7 u: V/ c
T data;
: S9 p ?# U2 D1 l Node<T> *next;
3 n% u; L+ s/ B6 h( a3 _7 i+ p v Node()
' i+ [: N# z: V {
G5 O( x' B: y% v' B this->next = NULL;
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Node(T data,Node<T> *next=NULL)' ]( }/ u2 `7 A* e* i8 e- T8 _
{
8 }" Y7 e/ {1 _/ }/ A this->data = data;3 U* G& w5 Y( j$ s, {9 {# B2 x
this->next = next;- C8 M7 I$ x( P4 E& u' g
}! |- u, `* G$ I |0 Y) C
};. p$ X% @+ v) @6 r/ i
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template <class T>
/ x) ], L; ^$ v. X2 Fclass LinkedStack
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private:
9 b% W7 u6 M. h, ]) d Node<T> *top;* f7 ?7 P+ Z5 G1 W
public:3 q: h! d0 p/ o" W* T- A# p
LinkedStack();( N3 y% [2 | H( ~+ _- F
~LinkedStack();- h/ R5 z# G, Q! T4 C, Y& b# U+ b( H
bool isEmpty();
: _2 i+ Q; P! N void push(T x);
1 f, v" c) O% s4 j T pop();$ t. z1 K' n" r s- \0 j% Y- K( R
T get();
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) P# {7 h0 b; @2 m# \, ` k0 |1 [, Xtemplate <class T>5 X9 l" z! J2 S. t$ R2 N; o
LinkedStack<T>::LinkedStack()8 \+ M! p- h. V4 \: M5 B
{
. v" s/ `6 K6 a! h4 v. k0 n) W- V) y top = NULL;
7 K3 Y$ m% }/ s/ A}
n0 r6 |1 y. V4 G
+ R+ t* C# h) h/ itemplate <class T>- i L3 i* O3 r
LinkedStack<T>::~LinkedStack()
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Node<T> *p = top;
- o4 g7 x5 F! X3 Y9 B4 Z! @ Node<T> *q;
. G D2 K# ^2 i, M L5 S while(p!=top)
, i" M! @- n- t' J {
: L$ B ?9 g5 a, W& T4 I0 H q = p;4 a" a- p0 u$ }7 C% g' Y
p = p->next;
4 r; {8 a# f8 j: k delete p;- I0 X" H2 y D f
}
) ]4 [! y* o9 D3 ^1 |+ y' y& M2 l; Z top = NULL;
+ q# v$ A# i* T5 R$ a, }# @9 e}7 @) l: h' ^+ z0 }, W, l p! \* L" e
9 L3 u5 I- c4 l0 gtemplate <class T>) r' o+ N, ~$ _# s9 M9 E
bool LinkedStack<T>::isEmpty()$ a8 h* M- n0 [7 [" s8 O e
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return top == NULL;4 m1 n3 D6 v: m) v
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4 o; Q" |- v2 ^0 J! gtemplate <class T>) M7 `/ Z0 M& h! k g$ M0 d
void LinkedStack<T>::push(T x)
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top = new Node<T>(x,top);7 q H5 ^4 b* m- w/ o
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$ x4 C( B: l$ @, y- u/ M: Itemplate <class T>, [2 d. `9 v: O0 [6 {; D1 B
T LinkedStack<T>::pop()
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$ M/ X& {) C! q9 {' O4 K+ V% E2 r if(!isEmpty())
+ y! r0 V5 ]5 W5 T+ o {
3 ^( N2 P7 f' }7 p T x = top->data;
* b' G$ u! X8 q* y7 D! e Node<T> *p = top;
2 F+ t2 p3 x0 L- C( }) P% B; T top = top->next;
% T* ^+ E' q4 Q- N" J3 c delete p;# Q' d2 j d) o- J
return x;
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throw "空栈,不能执行出栈操作";
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template <class T>
9 D8 m, c v+ f& TT LinkedStack<T>::get()0 i9 X* z' G- ^
{
, w( o$ z( P) ]/ Q if(!isEmpty())
7 J) J5 P/ E# W+ E& J4 H" [# m. s {
+ ]6 b( w& R: \1 t1 Z- v return top->data;- f8 K5 T/ X- ~% I" X w) _) |
}
, u1 t/ a1 h5 N f throw "空栈,不能获得栈顶元素";
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char * toPostfix(char *expstr)
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LinkedStack<char> stack;4 P9 d! `* `5 M8 l2 Z
char *postfix = new char[strlen(expstr)*2];' i' Z% u2 a1 N; }2 L" E2 v c
int i=0;
& {7 a: O0 R3 q0 ^2 I3 @ int j=0;/ p2 [ o3 O$ m& H$ g$ O! c
char out ;# ^9 w1 ~ q: F+ ?
while(expstr!='\0')
r: \+ X9 T& M% u1 I {
1 ^8 q; j o, W% @ switch(expstr)
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case'+':
, Z; A8 U# O8 r' A3 j, E9 w" C case'-':
& B; A- @0 w9 c5 q4 m) ? while(!stack.isEmpty()&&stack.get()!='(')
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postfix[j++] = stack.pop();+ G3 V* J' R- g/ a+ @
}
) F" E5 R) R0 M- N3 C, L9 u7 o stack.push(expstr[i++]);
2 J* r; G! @" l9 l v" k' T7 v break;+ k' X+ a5 K1 G' b9 G* R) o
case'*':
~, {+ l! M( u9 }/ W' r( x' q case'/':
* R v/ x2 V1 i/ B# X0 u while(!stack.isEmpty()&&(stack.get()=='*'||stack.get()=='/')), K% ]! B3 |) U( t9 k7 Z
{
| C1 l2 f- ~$ O6 { postfix[j++] = stack.pop();
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stack.push(expstr[i++]);
1 T5 R6 u2 E0 u' ?3 _$ P break;
6 k/ }' O3 q; G z" Y5 ?" T9 o3 N case'(':stack.push(expstr[i++]); w* |6 t) H) w, r6 U& ^
break;" M; Z C3 w1 ]+ E# W
case')':out = stack.pop();
4 w9 p. E5 P& V7 o1 g while(!stack.isEmpty()&&out!='(')
+ z1 b! ] R" \ N2 q* C {
. n! L& [' t3 ^, r( X postfix[j++] = out;
8 \# `* E2 H+ ^, f7 I' Z' \7 X out = stack.pop();
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i++;
. |7 H3 k4 K& u( Y8 B+ n! S7 N break;
! J. G, R& k, G$ c4 x1 S default:
$ L- t) \5 P E+ y while(expstr>='0'&&expstr<='9'&&expstr!='\0')0 X% l1 ^ a8 H0 O& |4 s7 t s. Q
{; X# @ s" g" K* r7 o
postfix[j++] = expstr[i++];
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0 v# G$ U- ?. p' i p& l0 _$ F% c postfix[j++]=' ';% r3 q# \( y1 ~, X2 d
break;/ r# g0 n7 o0 ^- ]7 N) D5 Z$ T7 B
}; z1 i' }, ~* J* |& C6 K; d* P
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while(!stack.isEmpty())8 g2 @/ E' s/ A7 W
{
' r# {8 s( ]) E' j postfix[j++]=stack.pop();
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postfix[j]='\0';
+ l5 y9 s& T) U1 d! a. A2 N return postfix;7 _( R/ _* Y: O3 b' j
}
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int value(char *postfix)
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LinkedStack<int> stack;' o8 g" |* t$ g* h
int i=0;
- T- K- P" Y! F9 x* a int result = 0;! D0 e) V# V0 R t
while(postfix!='\0')/ g( ]. ^9 `- S! R" u- [
{
" U( Y% h4 g, f( l0 _9 U1 ` if(postfix>='0'&&postfix<='9')
+ a: j9 Q9 j4 Y- g7 R5 z {+ ?) ~/ O1 g) C1 S
result = 0;
( ]4 \1 w' }- z+ A, t while(postfix!=' ')
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result = result*10+postfix[i++]-'0';2 _0 q' I2 Q0 @+ s
}! _! c4 a i* X( S: \
i++;1 O( R- v7 R* ~% w$ K2 }5 t8 M- p
stack.push(result);
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4 b6 k1 m" }! a$ w* Z% }1 W else
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if(postfix!=' ')4 T5 S( H% K. F3 r$ s5 v) G- C2 }8 l
{" b! [7 G8 k' R8 d- |
int y = stack.pop();
! A" a) Q) z% w; T int x = stack.pop();
+ Z% C8 ]* k% V: v7 H/ k7 d0 M8 x switch(postfix), x( a( R# {, C, d, I
{
. S/ _# A! B5 u C% w! X case'+':result = x + y;
) q( C9 {9 L t! s% l+ M break;) \6 g* [8 P( i" M. B2 X
case'-':result = x - y;0 j+ _6 n* }/ {' T+ w4 l& w( e
break;
2 X$ k& e# H4 [8 w. }8 T( i$ ] case'*':result = x *y;
: r# _7 o3 x! L: w9 O; l break;
P! X: t( W& P: ^" d' r case'/':result = x / y;
3 x9 M0 V* q! @ u4 z( U' N5 p break;
% V/ r S" v: s7 J1 ^ }
8 t" e( v8 ?- K! s3 W5 \% @+ `7 K) v stack.push(result);
9 j; Z+ }# k1 I) _1 } }
1 X7 M- O$ n3 V* ?, ?8 b, a. k i++;) c( ?. T3 Y6 {
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return stack.pop();5 X+ d! {+ l/ v; g3 D
}
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2 L }! x* o1 s1 y5 o3 aint main()
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1 `2 [& O2 q0 D //char *expstr = "121+10*(52-49+20)/((35-25)*2+10)";
! Y( v1 G! D: {" _ cout << "请输入表达式:";2 g) u+ v& s# L X9 Q' V
//char *a ;
/ @% b' q- c1 O! s5 l0 C, N: f //cin >> *a;) g$ w# d+ E2 Z, O) R ~( g
char expstr[20]={0};
5 i; ~2 `5 ?+ H8 s. {' s9 c; W while(1)
6 ?" L; @( ?4 Q! E6 Z4 W- t; |( W {2 I" r1 q9 V) C; J& u! [7 \2 J
cin>>expstr;
3 M7 Y+ m% p2 N: y$ n char *postfix = toPostfix(expstr);
4 a: R9 K! p9 Y* ~) \ cout << "expstr= "<<expstr << endl;
! E* L) L. C- x% G cout << "postfix= "<<postfix<<endl;1 Q9 B M2 Y6 U/ b# |( R
cout << "value= "<<value(postfix) << endl;: E2 {4 l+ |6 S$ Z
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return 0;- f/ R; j+ g2 i5 O
} |