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  1. #include <cstdlib>
  2. #include <cstdio> 
  3. #include <iostream>
  4. void evalPf(char*); 
  5. double cal(double, char, double); 
  6. using namespace std;
  7.  
  8. int main(int argc, char *argv[])
  9. {
  10.     char input[50];
  11.     cin.unsetf(ios::skipws); 
  12. 	cin>>input;      
  13.     evalPf(input);  
  14.     system("PAUSE");
  15.     return EXIT_SUCCESS;
  16. }
  17. void evalPf(char* postfix) { 
  18.     double stack[80]; 
  19.     char temp[2]; 
  20.     char token; 
  21.     int top = 0, i = 0;  
  22.     temp[1] = '\0';  
  23.     while(1) { 
  24.         token = postfix[i]; 
  25.         switch(token) { 
  26.             case '\0': 
  27.                 printf("ans = %f\n", stack[top]); 
  28.                 return; 
  29.             case '+': case '-': case '*': case '/': 
  30.                 stack[top-1] = 
  31.                        cal(stack[top-1], token, stack[top]); 
  32.                 top--; 
  33.                 break; 
  34.             default: 
  35.                 if(top < sizeof(stack) / sizeof(float)) { 
  36.                     temp[0] = postfix[i]; 
  37.                     top++; 
  38.                     stack[top] = atof(temp); 
  39.                 } 
  40.                 break; 
  41.         } 
  42.         i++; 
  43.     } 
  44. }
  45. double cal(double p1, char op, double p2) { 
  46.     switch(op) { 
  47.         case '+': 
  48.             return p1 + p2; 
  49.         case '-': 
  50.             return p1 - p2; 
  51.         case '*': 
  52.             return p1 * p2; 
  53.         case '/': 
  54.             return p1 / p2; 
  55.     } 
  56. }
Success #stdin #stdout 0.02s 5312KB
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stdin
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Standard input is empty
stdout
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ans = 0.000000
https://ideone.com/s0xf4
language:
C++ (gcc 8.3)
created:
13 years ago
visibility:
public

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