/* * Copyright (c) 2012 Fang Ying (Y. Fang), NEU Electric Engineering 20092725 ,fangying7@gmail.com * Copyright (c) GPLv3 * All Rights Reserved. * This program is free software; *you can redistribute it and/or modify it under the terms of the GNU General Public License V3 as published by the * Free Software Foundation, either version 2 or any later version. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * This program is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. A copy of the GNU General Public License is available at: * http://www.fsf.org/licensing/licenses */ #ifndef _SQ_STACK_H_ #define _SQ_STACK_H_ #include <iostream> using namespace std; template <class T> //模板声明 class sq_stack { private: int max; //存储空间容量 int top; //栈顶指针 T *s; //顺序栈的存储空间首地址 public: sq_stack(int max); //构造函数，建立空栈 ~sq_stack(); //析构函数 void print(); //顺序输出栈顶指针和栈中的元素 int flag(); //检测顺序栈的状态 void push(T); //压栈 T pop(); //弹栈 T read(); //读取栈顶数据 }; //建立容量为max的空栈 template <class T> sq_stack<T>::sq_stack(int max) { this->max = max; //存储空间 s = new T[max]; //申请内存空间 top = 0; return; } //顺序输出栈顶指针与栈中的元素 template <class T> void sq_stack<T>::print() { int i; cout<<"top = "<<top<<endl; for (i = top ;i > 0 ;i--) cout<<s[i-1]<<endl; return; } //检测顺序栈的状态 template <class T> int sq_stack<T>::flag() { if (top == max) return(-1); //存储空间已满，返回-1 if (top == 0) return(0); // return (1); } //压栈 template <class T> void sq_stack<T>::push(T x) { if (top == max) { cout<<"stack overflow!"<<endl; return; } top++; //栈顶指针进1 s[top - 1] = x; //新元素入栈 return; } //弹栈 template <class T> T sq_stack<T>::pop() { T y; if (top == 0) { cout<<"underflow!"<<endl; return -1; } y = s[top-1]; top -= 1; return y; } //读取栈顶元素 template <class T> T sq_stack<T>::read() { if (0 == top) {cout<<"Stack empty!"<<endl; return -1;} return s[top - 1]; //返回栈顶元素 } //书序表空间回收 template <class T> sq_stack<T>::~sq_stack() { delete s; } #endif
#include "sq_stack.h" int main() { sq_stack<int> st(10); st.push(50); st.push(60); st.push(46); st.push(465); st.push(712); st.push(2747); cout<<"输出战中的元素："<<endl; st.print(); cout<<"栈顶元素:"<<st.read()<<endl; cout<<"输出退栈元素:"<<endl; cout<<st.pop()<<endl; cout<<st.pop()<<endl; cout<<st.pop()<<endl; cout<<"再次输出栈顶指针和栈中的元素"<<endl; st.print(); return 0; }
#include "sq_stack.h" #include <cstdio> #include <cstdlib> #include <cmath> #include <iostream> using namespace std; /*======================================================*/ /* 转换当前字符为实数 */ /*======================================================*/ double char2double(char *s, int *k) { double x,y = 1.0; int fla g = 1; char c; x = 0.0; c = s[*k]; //取得当前符号 while(c >= '0'&& c<'9' ||c=='.') { *k = *k + 1; //扫描指针加一 if (c >= '0'&& c<='9') if(0 == flag) //转换小数后的值，并将整数部加上 {y = y*0.1; x=x+(c-48)*y;} else x=10*x+(c-48); else flag = 0; c = s[*k]; } return (x); } /* ====================================================*/ /* 判断运算符的优先级 */ /* ====================================================*/ int priority(char op) { int k = 0; switch(op) { case '^': k = 3;break; case '*': k = 2;break; case '/': k = 2;break; case '+': k = 1;break; case '-': k = 1;break; case '(': k = 0;break; case ')': k = 0;break; case '\0': k = -1;break; default: k = -2;break; } return (k); } int main() { sq_stack<double> sd(50); //操作数栈 sq_stack<char> sp(20); //操作符栈 char s[60],c; //s[60]存放输入的待处理字串 int flag =1 ,k; double x, y; //左右操作数 sp.push('\0'); //表达式结束符进入运算符栈 cout<<"input formula:"<<endl; cin>>s; k = 0; //扫描指针初始化 c = s[k]; //取得当前字符 while(flag) { if ((c >= '0')&&( c<='9')||(c == '.')) //当前字符为数字字符或者小数点 sd.push(char2double(s ,&k)); //double atof(const char *ptr)将输入的字符串转换为浮点型数据 else if ((c == '(') || priority(c) > priority(sp.read())) //当前符号位"("或者运算符的优先级大于运算符栈的栈顶运算符优先级 { sp.push(c); //运算符入栈 k++; //扫描指针加一 } else if ((c == '\0')&&(sp.read() == '\0')) flag = 0; else if ((c == ')')&&(sp.read() == '(')) //当前符号为")"，且运算符栈栈顶运算符为"(" { sp.pop(); //从运算符栈顶退出左括号 k++; //扫描指针加一 } else if (priority(c) <= priority(sp.read())) //当前符号为")"，且运算符优先级不大于运算符栈栈顶的优先级 { y = sd.pop(); //从操作数栈取右操作数 x = sd.pop(); //从操作数栈取左操作数 c = sp.pop(); //从运算符栈取运算符 switch(c) { case '^': x = pow(x,y);break; case '*': x = x*y;break; case '/': x = x/y;break; case '+': x = x+y;break; case '-': x = x-y;break; } sd.push(x); //将计算结果放回操作数栈 } c = s[k]; //取得字符 } cout<<s<<"="<<sd.read()<<endl; //输出计算结果 return 0; }