数据结构——链表栈实现算术表达式的运算

1、 design a "automatic calculator" as follows：

（1）The expression that needs to be calculated is stored in the text file in the TXT text；

（2）Each line in the text is an expression；

（3）Expressions include operands, operators such as addition, subtraction, multiplication and division, and parentheses；

     For example： （34-72.3）*54.7-82.4

（4）"Automatic calculator" calculates each expression in the text file according to the input file name, and writes every expression of the result to the original file name in the _out.txt, you should use the method of covering and when saving the records. The format of each row is：

    expression = result。

     For example：the original file is: A1.txt

           The file for output is： A1_out.txt

           The format of the text in A1_out.txt is：

               （34-72.3）*54.7-82.4 = -2177.41

     For all the calculated results, you'd keep 4 digits after the decimal point if it is decimal.

（5）Generate a statistical document after the calculation, its content is：

     Execution time：xxxx-xx-xx hh:mm:ss

     The total number of expressions is：XXX

     The number of correct expressions is：XXX

     The number of error expressions is：XXX

     Naming rules for filenames：original file name :_log.txt，Write files with append write method。

      For example：A1.txt corresponding to the statistical file：A1_log.txt

 

  1 #include <iostream>
  2 #include <stack>
  3 #include <string>
  4 #include<sstream>
  5 #include<fstream>
  6 #include<time.h>
  7 #include<Windows.h>
  8 
  9 //栈的实现头插法
 10 using namespace std;
 11 
 12 
 13 struct stacks{
 14     float data;
 15     stacks *next;
 16 };
 17 
 18 struct stacks_op{
 19     char data;
 20     stacks_op *next;
 21 };
 22 
 23 stacks *st;
 24 stacks_op *op;
 25 bool empty(int n);
 26 void push1(float data);
 27 void push2(char data);
 28 float top1();
 29 char top2();
 30 void pop(int n);
 31 
 32 bool isNumber(char s);
 33 float stringToNum(string s);
 34 int priority(char op);
 35 
 36 
 37 int main() {
 38     DWORD fin_start, fin_stop;
 39     fin_start = GetTickCount();
 40     DWORD start, stop;
 41     
 42     int cnt__ = 0;
 43     int cnt_ = 0;
 44     st = new stacks;
 45     op = new stacks_op;
 46     st->next = NULL;
 47     op->next = NULL;
 48 
 49     string s1 = "A1.txt";
 50     ifstream infile(s1.c_str());
 51 
 52     if (infile.fail()) {
 53         cerr << "file empty" << endl;
 54         abort();
 55     }
 56 
 57     string suffix = "suffix.txt";
 58     //ofstream outfile(suffix.c_str());
 59     ofstream out("A1_out.txt");
 60     string str;
 61 
 62     while (!infile.eof()) {
 63         cnt__++;
 64         start = GetTickCount();
 65         getline(infile, str);
 66         cout << str;
 67         int len = str.length();
 68 
 69         for (int i = 0; i < len; i++) {
 70             string tmp = "";
 71             if (isNumber(str.at(i))) {
 72                 tmp.append(1, str.at(i));
 73                 for (i = i + 1; i < len; i++) {
 74                     if (isNumber(str.at(i))) {
 75                         tmp.append(1, str.at(i));
 76                     }
 77                     else break;
 78                 }
 79                 i--;
 80                 float temp = stringToNum(tmp);
 81                 push1(temp);
 82                 //outfile << temp << " ";
 83             }
 84             else {
 85                 char oper = str.at(i);
 86                 switch (oper) {
 87                 case '(':
 88                     push2(oper);  //当前运算符为'('直接压栈
 89                     break;
 90                 case ')':
 91                     //将栈中元素弹出加到后缀表达式尾,直到遇到运算符"("
 92                     while (top2() != '(') {
 93                         char op = top2();
 94                         float a = top1();
 95 
 96                         pop(1);
 97                         float b = top1();
 98                         pop(1);
 99                         float c;
100 
101                         switch (op)
102                         {
103                         case '+':
104                             c = a + b;
105                             break;
106                         case '-':
107                             c = b - a;
108                             break;
109                         case '*':
110                             c = b / a;
111                             break;
112                         case '/':
113                             c = b / a;
114                             break;
115                         default:
116                             break;
117                         }
118                         push1(c);
119                         
120                         //outfile << top2() << " ";
121                         pop(2);
122                     }
123                     pop(2);
124                     break;
125                 case '+':
126                 case '-':
127                 case '*':
128                 case '/':
129                     while (!empty(2) && priority(top2()) >= priority(oper)) {
130                         char op=oper;
131                         if (priority(top2()) == priority(oper)) {
132                             
133                             op = top2();
134                             pop(2);
135                             push2(oper);
136                             //cout << "push " << oper << endl;
137                         }
138                         if (priority(top2()) > priority(oper)) {
139 
140                             op = top2();
141                             pop(2);
142                             push2(oper);
143                         }
144                         float a = top1();
145                         
146                         pop(1);
147                         float b = top1();
148                         pop(1);
149                         float c;
150                         
151                         switch (op)
152                         {
153                         case '+':
154                             c = a + b;
155                             break;
156                         case '-':
157                             c = b - a;
158                             break;
159                         case '*':
160                             c = b*a;
161                             break;
162                         case '/':
163                             c = b / a;
164                             break;
165                         default:
166                             break;
167                         }
168                         push1(c);
169 
170                         //outfile << top2() << " ";
171                         pop(2);
172                     }
173                     push2(oper);
174                 default:
175                     break;
176                 }
177 
178             }
179         }
180         while (op->next != NULL) {
181             char oper = top2();
182 
183             float a = top1();
184             pop(1);
185             float b = top1();
186             pop(1);
187             float c;
188             switch (oper)
189             {
190             case '+':
191                 c = a + b;
192                 break;
193             case '-':
194                 c = b - a;
195                 break;
196             case '*':
197                 c = b*a;
198                 break;
199             case '/':
200                 c = b / a;
201                 break;
202             default:
203                 break;
204             }
205             push1(c);
206             //outfile << top2() << " ";
207             pop(2);
208             
209         }
210         //outfile << endl;
211         stop = GetTickCount();
212         out << str << "=" << top1() << "      ";
213         double t = (stop - start)*1.0 / 1000;
214         out << "执行运算时间为：" << t << endl;
215         cout << "=" << top1() << endl;
216         cnt_++;
217     }
218     fin_stop = GetTickCount();
219     double tt = (fin_stop - fin_start)*1.0 / 1000;
220     out << "执行总的运算时间为：" << tt << endl;
221     out << "总的表达式数量为：" << cnt__ << endl;
222     out << "正确表达式数量为：" << cnt_ << endl;
223     out << "错误表达式数量为：" << (cnt__-cnt_) << endl;
224 
225     out.close();
226     //outfile.close();
227     infile.close();
228     system("pause");
229 }
230 
231 bool empty(int n) {
232     if (n == 1) {
233         if (st->next == NULL) {
234             return true;
235         }
236         return false;
237     }
238     else if(n==2) {
239         if (op->next == NULL) {
240             return true;
241         }
242         return false;
243     }
244 }
245 
246 void push1(float data) {
247         stacks *q = new stacks;
248         q->next = NULL;
249         q->data = data;
250         q->next = st->next;
251         st->next = q;
252 }
253 
254 void push2(char data) {
255     stacks_op *q = new stacks_op;
256     q->data = data;
257     q->next = op->next;
258 
259     op->next = q;
260 }
261 
262 float top1() {
263     stacks* p = st->next;
264     return p->data;
265 }
266 
267 char top2() {
268     if (op->next == NULL) {
269         cout << "top2 empty" << endl;
270     }
271     stacks_op *p = op->next;
272     return op->next->data;
273 }
274 
275 void pop(int n) {
276     if (n == 1) {
277         stacks *p = st->next;
278         st->next = p->next;
279         delete p;
280         
281     }
282     else {
283         stacks_op *p = op->next;
284         op->next = p->next;
285         delete p;
286     }
287 }
288 
289 /**
290 *判断当前字符是否为数字
291 */
292 bool isNumber(char s) {
293     string opers = "+-*/()";
294     for (int i = 0; i < opers.length(); i++) {
295         if (s == opers.at(i)) {
296             return false;
297         }
298     }
299     return true;
300 }
301 
302 /**
303 * 判断当前运算符与栈顶运算符的优先级大小
304 */
305 float stringToNum(string str) {
306     stringstream ss(str);
307     float num;
308     ss >> num;
309     return num;
310 }
311 
312 int priority(char op) {
313     switch (op)
314     {
315     case '(':
316     case ')':
317         return 0;
318     case '+':
319     case '-':
320         return 1;
321     case '*':
322     case '/':
323         return 2;
324     default:
325         return -1;
326     }
327 }
MAIN.cpp
1 (34.78+89.89)*12/67+673-342
2 89+56/32+67-32/4-23
3 67+67-32.43+77*5+78/32
4 89+73.231-(33.32*67-32.647+6723)
5 78+60*(6+73-5)-23+67+23
6 9999.99999+11111.11111
A1.txt
posted @ 2018-11-07 22:45  明楼  阅读(404)  评论(0)    收藏  举报