7-1 Expression conversions (25 points)

Topic:

The arithmetic expression has the form of prefix notation, infix notation and suffix notation. The arithmetic expression used in daily use is infix notation, that is, the two-dollar operator is in the middle of two operands. Please design your program to convert infix expressions to suffix expressions.

Input format:

The input gives an infix expression with no spaces in one line, which can contain,, + - * , \ and left and right brackets, with an () expression of no more than 20 characters.

Output format:

outputting the converted suffix expression on a single line requires that different objects (operands, operation symbols) be separated by a space, but with no extra space at the end.

Ideas:

Thanks to the big guy blog inspired over the card for one weeks title: https://www.cnblogs.com/8023spz/p/7635353.html

To summarize:

1. Build an empty stack storage operator

2, when the digital direct output, the value of the attention is that the number may be a decimal, negative (minus and number is output together) or with a positive number;

3, when encountered operator, the first comparison of the current symbol A and the top of the stack symbol B operation priority size, if a > b directly into the stack, otherwise the output stack operator until empty or stack top element as ' (';

4, when encountering ') ' operator, directly output the operator in the stack until the stack is empty or encounters the operator ' (';

5. The last operator in the output stack until the stack is empty.

6, the most card format is a case of the operator and the right parenthesis consecutive occurrences such as a (+5)-1, to carefully consider the processing of the output format;

The first is the code of the +5-1 card to vomiting blood:

#include <bits/stdc++.h>using namespacestd;Const intMAXN = 1e4 +Ten; typedefLong LongLl;stack<Char>STA;intMain () {map<Char,int>MP; stringstr; CIN>>str; BOOLIsfirst =true; mp['-'] =1, mp['+'] =1; mp['*'] =2, mp['/'] =2; mp['('] =3, mp[')'] =3;  for(inti =0; I<str.size (); i++) {        if(((i==0|| str[i-1]=='(') && (str[i]=='+'|| Str[i] = ='-')) || (str[i]>='0'&&str[i]<='9') || (str[i]=='.')) {            if(str[i]!='+') {                if(!isfirst) {////Carefully consider the position processing of the first output format, enter the (+5)-1cout<<" ";////Output 25 + 1-, malformed, in order to find this error, give an example to want to die}////cout<<Str[i]; }             while(str[i+1]=='.'|| (str[i+1]>='0'&& str[i+1]<='9') ) {i++; cout<<Str[i]; } Isfirst=false; } Else {            if(str[i]==')') {                 while(!sta.empty () && sta.top ()! ='(') {cout<<' '<<Sta.top ();                Sta.pop ();            } sta.pop (); } Else if(Sta.empty () | | Mp[str[i]] >mp[sta.top ()])            {Sta.push (str[i]); } Else {                 while(!sta.empty () && sta.top ()! ='(') {cout<<' '<<Sta.top ();                Sta.pop ();            } sta.push (Str[i]); }        }    }     while(!Sta.empty ()) {cout<<' '<<Sta.top ();    Sta.pop (); }    return 0;}/*Input Sample: 2+3* (7-4) +8/4 sample output: 2 3 7 4-* + 8 4/+*/

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Correct the full-pair code:

#include <bits/stdc++.h>using namespacestd;Const intMAXN = 1e4 +Ten; typedefLong LongLl;stack<Char>STA;intMain () {map<Char,int>MP; stringstr; CIN>>str; BOOLIsfirst =true; mp['-'] =1, mp['+'] =1; mp['*'] =2, mp['/'] =2; mp['('] =3, mp[')'] =3;  for(inti =0; I<str.size (); i++) {        if(((i==0|| str[i-1]=='(') && (str[i]=='+'|| Str[i] = ='-')) || (str[i]>='0'&&str[i]<='9') || (str[i]=='.')) {            if(!Isfirst) {cout<<" "; }            if(str[i]!='+') {cout<<Str[i]; }             while(str[i+1]=='.'|| (str[i+1]>='0'&& str[i+1]<='9') ) {i++; cout<<Str[i]; } Isfirst=false; } Else {            if(str[i]==')') {                 while(!sta.empty () && sta.top ()! ='(') {cout<<' '<<Sta.top ();                Sta.pop ();            } sta.pop (); } Else if(Sta.empty () | | Mp[str[i]] >mp[sta.top ()])            {Sta.push (str[i]); } Else {                 while(!sta.empty () && sta.top ()! ='(') {cout<<' '<<Sta.top ();                Sta.pop ();            } sta.push (Str[i]); }        }    }     while(!Sta.empty ()) {cout<<' '<<Sta.top ();    Sta.pop (); }    return 0;}

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7-1 Expression conversions (25 points)