利用顺序栈计算后缀表达式（逆波兰表达式）

来源：互联网发布：网络即时通讯工具编辑：程序博客网时间：2024/06/02 03:31

#include <iostream>#include <cstdio>#include <cstring>using namespace std;#define MaxSize 50struct SeqStack{    double data[MaxSize];    int top;};bool InitStack(SeqStack *S){    S->top=-1;    return true;}bool Push(SeqStack *S,double x){    S->top++;    S->data[S->top]=x;    return true;}bool Pop(SeqStack *S,double &s){    s=S->data[S->top];    S->top--;    return true;}void DoOperator(SeqStack *S,char ch){    double left,right,value;    Pop(S,right);    Pop(S,left);    switch(ch)    {        case '+':value=left+right;Push(S,value);break;        case '-':value=left-right;Push(S,value);break;        case '*':value=left*right;Push(S,value);break;        case '/':            if(right==0) cout<<"错误"<<endl;               else value=left/right;Push(S,value);break;    }    return ;}int main(){    SeqStack S;    InitStack(&S);    double operand,result;    char ch;    while(cin>>ch) {        if(isdigit(ch))        {cin.putback(ch);                //是操作数则将字符放回输入流(可能要输入的是12,2.5等等大于10或者非整数，用double变量保存        cin>>operand;                     //重新读取操作数        Push(&S,operand);                   //操作数压栈        }        else DoOperator(&S,ch);    }    Pop(&S,result);    cout<<result<<endl;    return 0;}

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