CodePudding user response:

 # include 
#include 
#include 
//# include "header. H" 
Void main () 
{
SqStack OPTR OPND; 
OperandType a, b, d, x, theta. 
Char c; Deposit//keyboard input string???? 
Char z [6].//store integer string 
int i,j; 
Int s=1; 
The menu (); 
InitStack (& amp; OPTR);//initialization operator stack 
Push (& amp; OPTR, '=');//=expression is end 
InitStack (& amp; OPND);//initialize the operand stack 
Do {
The scanf (" % d ", & amp; J); 
The switch (j) {
Case 1://1. The input expression 
Printf (" input expression \ n "); 
The scanf (" % c ", & amp; c);//the scanf (" % s ", c); Where c is a single character, not string error 1 
break; 
Case 2://2. The output expression 
Printf (" % c ", c);//printf (" % s ", c); Error 2 
break; 
Case 3://3. Judge whether the bracket of the expression matching and calculating the value of the expression 
GetTop (& amp; OPTR, & amp; x); 
While (c!='=' | | x!='=') 
{
If (In (c))//is one of the seven kinds of operator 
{
The switch (Precede (x, c)) 
{
Case '& lt; "://currently has pressure stack after an operator (x) than an operator (c) low, will press c stack 
Push (& amp; OPTR, c); 
c=getchar(); 
break; 
Case: '=' 
Pop (& amp; OPTR, & amp; x);//to take off the brackets and receive the next character 
c=getchar(); 
break; 
Case '& gt; ': 
Pop (& amp; OPTR, & amp; Theta);//return stack operation and the result was pressed into the OPND 
Pop (& amp; OPND, & amp; B); 
Pop (& amp; OPND, & amp; A); 
Push (& amp; OPND to Operate (a, theta, b)); 
break; 
} 
} 
Else if (c & gt;='0' & amp; & C & lt;='9')//c is the operand 
{
I=0; 
Do {
Z [I]=c; 
I + +; 
c=getchar(); 
} while (c & gt;='0' & amp; & C & lt;='9'); 
[I] z=0; 
D=atoi (z);//a character array to integer in d 
Push (& amp; OPND, d); 
} 
Else for illegal characters//c 
{
Printf (" ERROR3 \ n "); 
exit(1); 
} 
GetTop (& amp; OPTR, & amp; x); 
} 
GetTop (& amp; OPND, & amp; x); 
StackDestroy (& amp; OPTR); 
StackDestroy (& amp; OPND); 
Printf (" % d \ n ", x); 
break; 
Case 4://4. Out 
S=0; 
break; 
} 
} while (s==1); 
Printf (" have withdrawn from the \ n "); 
}