Bài viết sưu tầm

#include<iostream>

#include<math.h>

using namespace std;

struct Node

{

  int Data;

  Node *Next;      

};typedef Node * Stack;

Node *TaoNut(int X)

{

 Node *p;p=new Node;

 p->Data=X;

 return p;

 }

void CreateStack(Stack &S)

{

  S=NULL;  

}   

bool isEmpty(Stack S)

 {

     return (S==NULL);

 }   

 void Push(Stack &S,int X)

 {

  Node *p;

  p=TaoNut(X);

  p->Next=S;

  S=p;   

 }

 int Top(Stack S)

 {

    if(S!=NULL) 

    return S->Data;

 }

 void Pop(Stack &S)

 {

   Node *p;

   if(S!=NULL)

   {

    p=S;S=S->Next;

    delete(p);

   }

 }

 

 bool istoanhang(char c)

{

            return (c!='+' && c!='-' && c!='*' &&c!='/'&&c!='^');

}

bool istoantu(char c)

{

            return (c=='+' || c=='-' || c=='*' ||c=='/'||c=='^');

}

int TinhToan(int a, int b, char c)

{

            switch (c) {

                        case '+': return b+a;

                        case '-': return b-a;

                        case '/':

                                    if (a ==0) cout<<"Chia cho 0";

                                    else return b/a;

                        case '*': return b*a;

                        case '^': return (int)pow(b,a);

            }

}

 void in_S(Stack S)

 {

      Node *p;

      for(p=S;p!=NULL;p=p->Next)

       cout<<p->Data;

 }

 void in_P(int t, char P[])

 {

      for(int k=t;k<strlen(P);k++)

       cout<<P[k];

 }

int dinhgia(char* str)

{

            int a, b;

            Stack S;

            CreateStack(S);

            int i = 0;

            while (i < strlen(str))          

            {

                        if (istoanhang(str[i])) Push(S, int(str[i]-'0'));

                        else if (istoantu(str[i])) {

                                    a = Top(S);

                                    Pop(S);

            b = Top(S);

                                    Pop(S);

                                    Push(S, TinhToan(a, b, str[i]));

                                   

      }

      in_S(S);cout<<"\t"; in_P(i,str);cout<<"\n";

      i++;

            }

            return Top(S);

}

 

int main()

{

   cout<<" ket qua la :"<<dinhgia("521-+2^53+-")<<"\n";

  //cout<<2^2;

    system("pause");

}