# include & lt; stdio.h> 
# include & lt; Stdlib. H> 
#include 

//operator stack 
Typedef struct SChar {
Char data; 
Struct SChar * next; 
} SChar, * LinkStack; 

//the operand stack 
Typedef struct SNum {
Float data; 
Struct SNum * next; 
} SNum, * LinkStack2; 

//char initialization 
LinkStack InitChar () {
Return NULL; 
} 

//char stack 
LinkStack PushChar (LinkStack pTop, char e) {
SChar * S=(LinkStack) malloc (sizeof (SChar)); 
S - & gt; Data=https://bbs.csdn.net/topics/e; 
S - & gt; Next=pTop; 
PTop=S; 
Return pTop; 
} 

//char out stack 
LinkStack PopChar (LinkStack pTop, char * e) {
If (pTop==NULL) 
Printf (" empty stack! \n"); 
* e=pTop - & gt; The data; 
LinkStack p=pTop; 
PTop=pTop - & gt; Next; 
Free (p); 
Return pTop; 
} 

//num initialization 
LinkStack2 InitNum () {
Return NULL; 
} 

//num stack 
LinkStack2 PushNum (LinkStack2 pTop, float e) {
SNum * S=(LinkStack2) malloc (sizeof (SNum)); 
S - & gt; Data=https://bbs.csdn.net/topics/e; 
S - & gt; Next=pTop; 
PTop=S; 
Return pTop; 
} 

//num out stack 
LinkStack2 PopNum (LinkStack2 pTop, float * e) {
If (pTop==NULL) 
Printf (" empty stack! \n"); 
* e=pTop - & gt; The data; 
LinkStack2 p=pTop; 
PTop=pTop - & gt; Next; 
Free (p); 
Return pTop; 
} 

Float Cal (char a, float b, float c)//operation function, a is operator, b, c respectively two Numbers 
{
Float r=0; 
The switch (a) 
{
Case: '+' 
R=b + c; 
break; 
In case the '-' : 
R=b - c; 
break; 
Case: '*' 
R=b * c. 
break; 
Case '/' : 
If (c!=0) 
R=b/c; 
break; 
} 
Return r; 
} 

//infix expression evaluation 
Void the Count (char * STR) {
Char * p=STR. 
Char e; 
Float f, num=0, temp=0; 
LinkStack s=NULL; 
LinkStack2 q=NULL;//s check OPTR (operator), q hosting OPND (operand) 
S=InitChar (); 
Q=InitNum (); 
S=PushChar (s, '#'); 
While ((* p)! )='\ n' {
//read the operand 
//if the stack is empty, it directly into; If not null, stack top element judgment symbol: symbol stack as a '*', '/' hours calculation, or pressed into 
If (isdigit (* p)) {
Temp=(float) * p - '0'. 
If (isdigit (* (+ + p))) {
Temp=temp * 10 + (float) - '0' (* p). 
} the else 
P -; 
if(! Q) 
Q=PushNum (q, temp); 
Else if (s - & gt; Data=https://bbs.csdn.net/topics/='*' | | s - & gt; The data '/') {
 https://bbs.csdn.net/topics/==S=PopChar (s, & amp; E); 
Num=Cal (e, q - & gt; The data, temp); 
Q=PopNum (q, & amp; F); 
Q=PushNum (q, num); 
} the else 
Q=PushNum (q, temp); 
} 
//read in operator, 
The else {
If (s - & gt; Data='#') 
 https://bbs.csdn.net/topics/=S=PushChar (s, p); 
Else if (* p=='+' | | * p=='-') {
If (s - & gt; The data!='(') {
S=PopChar (s, & amp; E); 
Q=PopNum (q, & amp; F); 
Num=Cal (e, q - & gt; The data, f); 
Q=PopNum (q, & amp; F); 
Q=PushNum (q, num); 
} 
S=PushChar (s, p); 
} 
Else if (* p==') ') {
S=PushChar (s, p); 
While (s - & gt; The data!='(') {
If (s - & gt; Data='https://bbs.csdn.net/topics/=') 
S=PopChar (s, & amp; E); 
S=PopChar (s, & amp; E); 
Q=PopNum (q, & amp; F); 
Num=Cal (e, q - & gt; The data, f); 
Q=PopNum (q, & amp; F); 
Q=PushNum (q, num); 
} 
S=PopChar (s, & amp; E); 
} 
Else if (* p=='*' | | * p=='/') {
If (s - & gt; Data=https://bbs.csdn.net/topics/='*' | | s - & gt; The data '/') {
 https://bbs.csdn.net/topics/==S=PopChar (s, & amp; E); 
Q=PopNum (q, & amp; F); 
Num=Cal (e, q - & gt; The data, f); 
Q=PopNum (q, & amp; F); 
Q=PushNum (q, num); 
} 
S=PushChar (s, p); 
} 
Else if (* p=='(') 
S=PushChar (s, p); 
} 
P++; 
} 
While (s - & gt; The data!='#') {
Q=PopNum (q, & amp; F); 
Num=Cal (s - & gt; The data, the q - & gt; The data, f); 
If (q - & gt; Next) 
Q=PopNum (q, & amp; F); 
Q=PushNum (q, num); 
S=s - & gt; Next; 
} 
Num=q - & gt; The data; 
Printf (" % 2 f \ n ", num); 
} 

//infix expression suffix 
Void Conversion (char * STR) {
Char * p=STR. 
Char e; 
LinkStack top=NULL; 
Top=InitChar (); 
While (* p! )='\ n' {
//digital print directly 
If (isdigit (* p)) {
Char * t=p; 
If (isdigit (* (+ + p))) 
Printf (" % c "c %, * t, * p). 
The else {
P -; 
Printf (" % c ", * p). 
} 
} 
//the stack is empty, the press directly into the 
if(! Top & amp; & ! Isdigit (* p)) {
(top, top=PushChar * p); 
} 
//the stack is not empty 
The else {
If (* p=='+' | | * p=='-') {
//the stack is not empty, because the '+' '-' as the lowest priority, the absence of parentheses, the existing elements in the stack pop-up and print the 
While (top & amp; & Top - & gt; The data!='+' & amp; & Top - & gt; The data!='-' & amp; & Top - & gt; The data!='(') {
(top, top=PopChar & amp; E); 
Printf (" % c ", e); 
} 
(top, top=PushChar * p);//into the symbol 
} 
If (* p=='*' | | * p=='/') {
While (top - & gt; The data!='+' & amp; & Top - & gt; The data!='-' & amp; & Top - & gt; The data!='(') {
(top, top=PopChar & amp; E); 
Printf (" % c ", e); 
if(! Top) 
break; 
} 
(top, top=PushChar * p); 
} 
If (* p=='(') 
(top, top=PushChar * p); 
If (* p==') ') {
While (top - & gt; The data!='(') {
(top, top=PopChar & amp; E); 
Printf (" % c ", e); 
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