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중위 표현식을 후위 표현식으로 변환하는 코드를 작성했습니다. 표현식을 검사하기위한 두 가지 함수가 있는데, 하나는 괄호없이 표현식을 검사하고 다른 하나는 괄호로 표현식을 확인하고 변환하기위한 것입니다.중위 어와 후미 변환 괄호 오류
대괄호가 아닌 표현식을 변환하는 함수는 완전히 작동하지만 대괄호로 변환하는 함수는 오류를 발생시킵니다.
제가
입력 식 는 (a +가 B) * (C-d), 그것은 올바르게 + B를 변환 한 후 스택에 푸시 * 등을들 수있다. 그러나 어쨌든 프로그램은 (c-d)의 시작 브래킷을 브래킷으로 인식하지 않고 일반 (브래킷없이)처럼 계속 변환합니다. 왜 그것이 브래킷으로 인식하지 못하고 있는지 알지 못합니다.이 작은 문제는 전체 출력을 망치고 있습니다. ? 당신이 할 수있는while(c!='(');
후, checkBracedExpression()에서
class Stack
{
.
.
.
void push(char value) //push value onto top of stack
{
if(isFull()==true) //only possible when stack is not full
cout<<endl<<"Sorry! Stack is already full, no more entries allowed!"<<endl;
else //add value to top of stack is stack is not empty
{
top++;
array[top]=value;
cout<<endl<<value<<" pushed onto the stack!"<<endl;
}
}
char pop() //remove an element from the top
{
if(isEmpty()==true) //if stack empty, nothing can be popped
cout<<endl<<"Sorry stack empty! Nothing to be popped!"<<endl;
else // otherwise return element at located at the top
{
return array[top--];
cout<<endl<<array[top]<<" popped"<<endl;
}
}
bool checkPrecedence(char a, char b) // function to check the precedence of operators
{
int precA,precB;
switch(a) //assigning value for precedence to operator A
{
case '+':
precA=1;
break;
case '-':
precA=1;
break;
case '*':
precA=2;
break;
case '/':
precA=2;
break;
case '^':
precA=3;
break;
case '(':
precA=0;
break;
}
switch(b) //assigning value for precedence to operator A
{
case '+':
precB=1;
break;
case '-':
precB=1;
break;
case '*':
precB=2;
break;
case '/':
precB=2;
break;
case '^':
precB=3;
break;
case '(':
precB=0;
break;
}
if (precA<precB) //comparing precedence
return false;
else if (precA>precB)
return true;
else if (precA==precB)
return true;
}
void checkExpression(char expr[]) //function to convert expression without brackets
{
int i=0; //control character number of input
int j=0; //control character number of output
int iter=0; //keep track of iterations
int noStack=0; //to keep track of size of stack at a particular time
char ch=expr[i]; //taking first character from input
char c;
noStack=top+1;
cout<<endl<<strlen(expr)<<endl; //displaying length of expression
while(i<strlen(expr)) //keep checking until the whole expression is not checked
{
iter++;
if((ch=='+' || ch=='-' || ch=='*' || ch=='/' || ch=='^') && (isEmpty()==true)) // if we encounter an operator and stack is empty
{
push(ch); //push operator onto stack
noStack++;
cout<<endl<<retrieve_top();
}
if((noStack==1) && (iter==2)) //so that single operator in stack is not compared with itself and added to output
{
}
else if(ch=='+' || ch=='-' || ch=='*' || ch=='/' || ch=='^') //if we encounter an operator when stack already contains an operator
{
cout<<endl<<retrieve_top();
c=pop(); //pop the element on top
noStack--;
if(checkPrecedence(c,ch)== true) // and then compare the precedence of the 2
{
outputString[j]=c; //if top of stack has greater precedence, add it to output
j++;
cout<<endl<<c<<" added to output";
push(ch); //and push the other operator onto stack
noStack++;
if(noStack==2)
{
c=pop();
noStack--;
outputString[j]=c;
j++;
}
cout<<endl<<retrieve_top()<<endl;
}
else //otherwise first push the operator on stack which was previously on top and then push the other operator on top of it
{
push(c);
noStack++;
push(ch);
noStack++;
cout<<endl<<retrieve_top()<<endl;
}
}
else // otherwise, if operand encountered, add it to output
{
cout<<endl<<ch<<" added to output";
outputString[j]=ch;
j++;
}
i++;
ch=expr[i]; //check next character from expression
}
if((isEmpty()==false) && (i==strlen(expr))) //if input has ended and stack still contains operators
{
while(isEmpty()!=true) //keep popping and adding them to output until stack becomes empty
{
cout<<endl<<retrieve_top()<<endl;
c=pop();
noStack--;
cout<<endl<<retrieve_top();
cout<<endl<<c<<" added to output";
outputString[j]=c;
j++;
}
}
}
void checkBracedExpression(char expr[]) //function to convert expression containing brackets
{
int i=0; //control character number of input
int j=0; //control character number of output
int iter=0; //keep track of iterations
int noStack=0; //to keep track of size of stack at a particular time
char ch=expr[i]; //taking first character from input
char c;
noStack=top+1;
cout<<endl<<strlen(expr)<<endl;
while(i<strlen(expr))
{
iter++;
if (ch=='(') //if we encounter a bracket
{
do
{
if (ch=='+' || ch=='-' || ch=='*' || ch=='/' || ch=='^'||ch=='(') //and character input is an operator, push it on the stack
{
push(ch);
noStack++;
}
else //otherwise, add it to output
{
outputString[j]=ch;
j++;
cout<<endl<<ch<<" added to output";
}
i++;
ch=expr[i]; //check next character
}
while (ch!=')'); //keep checking until we reach)
if(ch==')') //when we reach)
{
do //keep popping elements until we encounter (in the stack
{
c=pop();
noStack--;
if (c=='(') //if (is encountered, ignore it
{}
else
{
outputString[j]=c; //otherwise, add it to output
j++;
cout<<endl<<c<<" added to output";
}
}
while(c!='(');
}
}
else // otherwise, continue normal expression checking
{
if((ch=='+' || ch=='-' || ch=='*' || ch=='/' || ch=='^') && (isEmpty()==true)) // if we encounter an operator and stack is empty
{
push(ch);
noStack++;
}
if((noStack==1) && (iter==2)) //so that single operator in stack is not compared with itself and added to output
{
}
else if(ch=='+' || ch=='-' || ch=='*' || ch=='/' || ch=='^') //if we encounter an operator when stack already contains an operator
{
//cout<<endl<<retrieve_top();
c=pop();
noStack--;
if(checkPrecedence(c,ch)== true)
{
outputString[j]=c;
j++;
cout<<endl<<c<<" added to output";
push(ch);
noStack++;
if(noStack==2)
{
c=pop();
noStack--;
outputString[j]=c;
j++;
}
}
else
{
push(c);
noStack++;
push(ch);
noStack++;
}
}
else
{
cout<<endl<<ch<<" added to output";
outputString[j]=ch;
j++;
}
i++;
ch=expr[i];
}
i++;
ch=expr[i];
if((isEmpty()==false) && (i==strlen(expr)))
{
while(isEmpty()!=true)
{
c=pop();
noStack--;
cout<<endl<<c<<" added to output";
outputString[j]=c;
j++;
}
}
}
}
void displayOutputString()
{
cout<<endl<<"Output String: "<<outputString<<endl;
}
.
.
.
};
int main()
{
char expression[50];
Stack object;
int option;
object.createStack();
do
{
cout<<endl<<"1.Convert simple expression."<<endl<<"2.Convert bracket expression."<<endl<<"3.Exit"<<endl<<"Your option: ";
cin>>option;
cout<<endl;
switch(option)
{
case 1:
cout<<endl<<"Enter the expression (in infix): ";
cin.ignore();
cin>>expression;
object.checkExpression(expression);
object.displayOutputString();
break;
case 2:
cout<<endl<<"Enter the expression (in infix): ";
cin.ignore();
cin>>expression;
object.checkBracedExpression(expression);
object.displayOutputString();
break;
}
}
while (option!=3);
return 0;
}
아니요, 차이는 없습니다. – leMS