[英]C++ Postfix calculator using stacks
I'm trying to a postfix expression calculator but I stuck on a problem. 我正在尝试使用后缀表达式计算器,但是我遇到了问题。 The calculator returns the wrong answer and I don't know why. 计算器返回错误的答案,我不知道为什么。 I've followed the program line by line and nothing should be wrong. 我已经逐行遵循了程序,应该没错。 heres my code so far: 到目前为止,这是我的代码:
char expression[] = {"321*+"};
int number1, number2;
char *pExpression = &expression[0];
char symbole;
PileInt pile;
pile.init(5);
while(*pExpression){
symbole = *pExpression;
if(symbole == '+' || symbole == '-' || symbole == '*' || symbole == '/'){
switch (symbole){
case '+':
number2 = pile.pop();
number1 = pile.pop();
pile.push(number1 + number2);
break;
case '-':
number2 = pile.pop();
number1 = pile.pop();
pile.push(number1 - number2);
break;
case '*':
number2 = pile.pop();
number1 = pile.pop();
pile.push(number1 * number2);
break;
case '/':
number2 = pile.pop();
number1 = pile.pop();
pile.push(number1 / number2);
break;
}
} else pile.push(symbole);
pExpression++;
}
cout<<pile.pop()<<endl;
and heres the methods: 这里是方法:
void PileInt::init(int taille){ //Methode pour initialiser une pile d'entier
_addr = new int [ _taille = taille ];
assert( _addr != 0 );
_sommet = 0;
}
void PileInt::push(int n){ //Methode pour mettre un entier au dessus de la pile
if ( ! pleine() )
_addr[ _sommet++ ] = n;
}
int PileInt::pop(){ //Methode pour sortir l'entier au dessus de la pile
return ( ! vide() ) ? _addr[ --_sommet ] : 0;
}
int PileInt::top(){
if( ! vide() )
return (_sommet - 1);
}
expression: 321*+ Console returns 2501, it should return 5. Thank you in advance. 表达式:321 * + Console返回2501,应该返回5。谢谢。
When you have a number - you are pushing on its ASCII value. 当您有一个数字时,您将继续使用其ASCII值。
You need to push on its value so change 您需要推动其价值,所以要改变
pile.push(symbole);
to 至
pile.push(symbole - '0');
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