1 #include <stdio.h>
  2 #include <stdlib.h>
  3 #include <math.h>
  4 #define OK 1
  5 #define ERROR 0
  6 int InputJudge(char c); //判断函数是否为数字
  7 float Calc(char optr, float num1, float num2);
  8 char PriorityJudge(char optr1, char optr2);
  9 int main()
 10 {
 11     char arrayChar[20];
 12     float arrayFloat[20] = {0};
 13     char tempChar, optr, c;
 14     float tempFloat, num1, num2;
 15     int topChar = 0;
 16     int topFloat = 0;
 17     int i;
 18     for (i = 0; i < 20; ++i)
 19     {
 20         arrayChar[i] = ‘0‘;
 21     }
 22     arrayChar[topChar] = ‘#‘;
 23     topChar++;
 24     c = getchar();
 25     while(c != ‘#‘ || arrayChar[topChar - 1] != ‘#‘)
 26     {
 27         if (InputJudge(c))
 28         {
 29             arrayFloat[topFloat] = (float)(c - ‘0‘);
 30             topFloat++;
 31             c = getchar();
 32             /* 当连续输入数字时,计算十位数和百位数 */
 33             while(InputJudge(c))
 34             {
 35                 topFloat--;
 36                 tempFloat = arrayFloat[topFloat];
 37                 arrayFloat[topFloat] = (float)(tempFloat * 10 + (c - ‘0‘));
 38                 topFloat++;
 39                 c = getchar();
 40             }
 41             if (c == ‘.‘)
 42             {
 43                 i = 1;
 44                 c = getchar();
 45                 do
 46                 {
 47                     topFloat--;
 48                     tempFloat = arrayFloat[topFloat];
 49                     tempFloat = tempFloat + ((c - ‘0‘) / pow(10, i));
 50                     i++;
 51                     arrayFloat[topFloat] = tempFloat;
 52                     topFloat++;
 53                     c = getchar();
 54                 }
 55                 while(InputJudge(c));
 56             }
 57         }
 58         else
 59         {
 60             tempChar = arrayChar[topChar - 1];
 61             switch(PriorityJudge(tempChar, c))
 62             {
 63             case ‘<‘:
 64                 arrayChar[topChar] = c;
 65                 topChar++;
 66                 c = getchar();
 67                 break;
 68             case ‘=‘:
 69                 topChar--;
 70                 c = arrayChar[topChar];
 71                 c = getchar();
 72                 break;
 73             case ‘>‘:
 74                 topChar--;
 75                 optr = arrayChar[topChar];
 76                 topFloat--;
 77                 num2 = arrayFloat[topFloat];
 78                 topFloat--;
 79                 num1 = arrayFloat[topFloat];
 80                 arrayFloat[topFloat] = Calc(optr, num1, num2);
 81                 topFloat++;
 82                 break;
 83             }
 84         }
 85     }
 86     while(topFloat != 0)
 87     {
 88         topFloat--;
 89         tempFloat = arrayFloat[topFloat];
 90         printf("%f\n", tempFloat);
 91     }
 92     return OK;
 93 }
 94 float Calc(char optr, float num1, float num2)
 95 {
 96     switch(optr)
 97     {
 98     case ‘+‘:
 99         return (num1 + num2);
100         break;
101     case ‘-‘:
102         return (num1 - num2);
103         break;
104     case ‘*‘:
105         return (num1 * num2);
106         break;
107     case ‘/‘:
108         return (num1 / num2);
109         break;
110     }
111 }
112 int InputJudge(char c)
113 {
114     switch(c)
115     {
116     case ‘0‘:
117     case ‘1‘:
118     case ‘2‘:
119     case ‘3‘:
120     case ‘4‘:
121     case ‘5‘:
122     case ‘6‘:
123     case ‘7‘:
124     case ‘8‘:
125     case ‘9‘:
126         return OK;
127         break;
128     case ‘.‘:
129     case ‘+‘:
130     case ‘-‘:
131     case ‘*‘:
132     case ‘/‘:
133     case ‘(‘:
134     case ‘)‘:
135     case ‘#‘:
136         return ERROR;
137         break;
138     default:
139         break;
140     }
141 }
142 char PriorityJudge(char optr1, char optr2)
143 {
144     int i, j;
145     char priorityTable[7][7] =
146     {
147         {‘>‘, ‘>‘, ‘<‘, ‘<‘, ‘<‘, ‘>‘, ‘>‘},
148         {‘>‘, ‘>‘, ‘<‘, ‘<‘, ‘<‘, ‘>‘, ‘>‘},
149         {‘>‘, ‘>‘, ‘>‘, ‘>‘, ‘<‘, ‘>‘, ‘>‘},
150         {‘>‘, ‘>‘, ‘>‘, ‘>‘, ‘<‘, ‘>‘, ‘>‘},
151         {‘<‘, ‘<‘, ‘<‘, ‘<‘, ‘<‘, ‘=‘, ‘0‘},
152         {‘>‘, ‘>‘, ‘>‘, ‘>‘, ‘0‘, ‘>‘, ‘>‘},
153         {‘<‘, ‘<‘, ‘<‘, ‘<‘, ‘<‘, ‘0‘, ‘=‘}
154     };
155     switch(optr1)
156     {
157     case ‘+‘:
158         i = 0;
159         break;
160     case ‘-‘:
161         i = 1;
162         break;
163     case ‘*‘:
164         i = 2;
165         break;
166     case ‘/‘:
167         i = 3;
168         break;
169     case ‘(‘:
170         i = 4;
171         break;
172     case ‘)‘:
173         i = 5;
174         break;
175     case ‘#‘:
176         i = 6;
177         break;
178     }
179     switch(optr2)
180     {
181     case ‘+‘:
182         j = 0;
183         break;
184     case ‘-‘:
185         j = 1;
186         break;
187     case ‘*‘:
188         j = 2;
189         break;
190     case ‘/‘:
191         j = 3;
192         break;
193     case ‘(‘:
194         j = 4;
195         break;
196     case ‘)‘:
197         j = 5;
198         break;
199     case ‘#‘:
200         j = 6;
201         break;
202     }
203     return priorityTable[i][j];
204 }