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  1. #include<bits/stdc++.h>
  2. using namespace std;
  3. string s;
  4. int sz , n , m;
  5. char ch, ch2;
  6. int operator_value( char op );
  7. void Infix_To_Postfix();
  8. stack < char > stk;
  9. int main()
  10. {
  11.     cin>>s;
  12.     Infix_To_Postfix();
  13.     return 0;
  14. }
  15. void Infix_To_Postfix()
  16. {
  17.     string temp;
  18.     sz = s.size();
  19.     for ( int i = 0; i != sz; i++ )
  20.     {
  21.         if ( s [ i ] >= 'a' && s [ i ] <= 'z' )temp += s [ i ];
  22.         else if ( s [ i ] == '(' )stk.push( s [ i ] );
  23.         else if ( s [ i ] == ')' )
  24.         {
  25.             while ( !stk.empty() && stk.top() != '(' )
  26.             {
  27.                 ch = stk.top();
  28.                 stk.pop();
  29.                 temp += ch;
  30.             }
  31.             stk.pop();
  32.         }
  33.         else
  34.         {
  35.             while ( !stk.empty() && operator_value( s [ i ] ) <= operator_value( stk.top() ) )
  36.             {
  37.                 ch = stk.top();
  38.                 stk.pop();
  39.                 if ( ch != '(' && ch != ')' )temp += ch;
  40.             }
  41.             stk.push( s [ i ] );
  42.         }
  43.     }
  44.     while ( !stk.empty() ){if(stk.top() != '(' && stk.top() != ')' )temp += stk.top();stk.pop();}
  45.     cout<<temp<<endl;
  46. }
  47. int operator_value( char op )
  48. {
  49.     if ( op == '^' )return 3;
  50.     if ( op == '*' || op == '/' )return 2;
  51.     if ( op == '+' || op == '-' )return 1;
  52.     return -1;
  53. }
Success #stdin #stdout 0s 4468KB
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https://ideone.com/QMBklG
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
secret

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