今天是个好日子!我是 C++ 新手(在 stackoverflow 中也是如此),我需要各位专家的帮助。即使没有错误或警告,此代码也有问题。它只是在程序执行时挂起。
该程序使用链表(堆栈)将中缀转换为后缀。
# include <iostream>
# include <cstring>
using namespace std;
struct node {
char data;
node *next;
};
node *top=NULL;
node *bottom=NULL;
node *entry;
node *last_entry;
node *second_last_entry;
void push(const char Symbol) {
entry=new node;
if(bottom==NULL) {
entry->data=Symbol;
entry->next=NULL;
bottom=entry;
top=entry;
}
else {
entry->data=Symbol;
entry->next=NULL;
top->next=entry;
top=entry;
}
}
const char pop( ) {
char Symbol=NULL;
if(bottom==NULL)
cout<<"\n\n\n\t *** Error : Stack is empty. \n"<<endl;
else {
for (last_entry=bottom; last_entry->next!=NULL; last_entry=last_entry->next)
second_last_entry=last_entry;
if(top==bottom)
bottom=NULL;
Symbol=top->data;
delete top;
top=second_last_entry;
top->next=NULL;
}
return Symbol;
}
void infix_to_postfix(const char *Infix) {
char Infix_expression[100]={NULL};
char Postfix_expression[100]={NULL};
strcpy(Infix_expression,"(");
strcat(Infix_expression,Infix);
strcat(Infix_expression,")");
char Symbol[5]={NULL};
char Temp[5]={NULL};
for(int count=0;count<strlen(Infix_expression);count++) {
Symbol[0]=Infix_expression[count];
if(Symbol[0]=='(')
push(Symbol[0]);
else if(Symbol[0]==')') {
Symbol[0]=pop( );
while(Symbol[0]!='(')
{
strcat(Postfix_expression,Symbol);
Symbol[0]=pop( );
}
}
else if(Symbol[0]=='^' || Symbol[0]=='*' || Symbol[0]=='/'
|| Symbol[0]=='+' || Symbol[0]=='-')
{
if(Symbol[0]=='*' || Symbol[0]=='/')
{
Temp[0]=pop( );
while(Temp[0]=='^' || Temp[0]=='*' || Temp[0]=='/')
{
strcat(Postfix_expression,Temp);
Temp[0]=pop( );
}
push(Temp[0]);
}
else if(Symbol[0]=='+' || Symbol[0]=='-')
{
Temp[0]=pop( );
while(Temp[0]!='(')
{
strcat(Postfix_expression,Temp);
Temp[0]=pop( );
}
push(Temp[0]);
}
push(Symbol[0]);
}
else
strcat(Postfix_expression,Symbol);
}
cout<<"\n\n Postfix Expression : "<<Postfix_expression;
}
int main( ) {
char Infix_expression[100]={NULL};
cout<<"\n\n Enter the Infix Expression : ";
cin>>Infix_expression;
infix_to_postfix(Infix_expression);
return 0;
}
请帮我!我是新手,没有你们我走不了多远。非常感谢!