我正在尝试使用自定义堆栈类以后缀形式计算方程式。由于某种原因,程序不断崩溃。
这里是堆栈头文件
#ifndef aStack_h
#define aStack_h
#include <string>
#include <iostream>
using std::string; using std::cout;
class aStack
{
private:
int top, size;
int *stack;
public:
aStack(int s)
{
size = s;
top = -1;
stack = new int [s];
}
~aStack()
{
delete [] stack;
}
void reset();
void push(int);
void pop();
int getTop();
void getSize()
{
std::cout << size;
}
};
#endif
类实现文件:
#include "aStack.h"
#include <iostream>
using namespace std;
void aStack::pop()
{
if (top == -1)
{ cout << "Stack is already empty.\n";}
stack[--top];
}
void aStack::push(int v)
{
if (top == size)
{ cout << "Stack is full.\n";}
stack[top++] = v;
}
void aStack::reset()
{
top = -1;
}
int aStack::getTop()
{
return top;
}
这里是主程序
#include <iostream>
#include "aStack.h"
#include <string>
using namespace std;
int main()
{
string equation {"35+1*"};
int op, count = 0, *oparray, result;
aStack stack(equation.length());
for (int i = 0; i < equation.length(); i++)
{
if (isdigit(equation[i]))
{
stack.push(equation[i]);
count++;
}
else
{
oparray = new int [count];
for (int o = 0; o < count; o++)
{
oparray[o] = stack.getTop();
stack.pop();
}
switch(equation[i])
{
case '+':
for (int i =0; i < count; i++)
{
op += oparray[i];
count--;
}
stack.push(op);
break;
case '-':
for (int i =0; i < count; i++)
{
op-=oparray[i];
count--;
}
stack.push(op);
break;
case '*':
for (int i =0; i < count; i++)
{
op*=oparray[i];
count--;
}
stack.push(op);
break;
case '/':
for (int i =0; i < count; i++)
{
op/=oparray[i];
count--;
}
stack.push(op);
break;
}
delete [] oparray;
}
}
result = stack.getTop();
cout << result;
}
我知道我不应该使用“ using namespace std;”,我很着急。我怀疑那会成为我麻烦的原因。任何帮助是极大的赞赏。
您的堆栈类已经在注释中指出了其他问题。修复这些问题后,主程序中只剩下一些错误。
我在您的数组中使用了std::unique_ptr<>
而不是原始指针,并禁用了移动语义,因此它既不可复制(由于[C0]),也不可移动。
如果您试图越界访问堆栈,我也添加了抛出异常。
unique_ptr
关于主程序,主要问题是您忘记了将每个数字的ASCII值转换为整数。另一个问题是#include <cctype>
#include <cstddef>
#include <exception>
#include <iostream>
#include <memory>
#include <stdexcept>
#include <string>
#include <utility>
template<typename T>
class aStack {
public:
using value_type = T;
explicit aStack(size_t c) :
cap(c), stored(0), stack(std::make_unique<value_type[]>(cap)) {}
aStack(aStack&&) = delete; // moving disabled
void reset() noexcept { stored = 0; }
void push(const value_type& v) {
if(stored == cap) throw std::runtime_error("stack is full");
stack[stored++] = v;
}
void push(value_type&& v) {
if(stored == cap) throw std::runtime_error("stack is full");
stack[stored++] = std::move(v);
}
value_type& pop() {
if(stored == 0) throw std::runtime_error("stack is empty");
return stack[--stored];
}
[[nodiscard]] const value_type& top() const {
if(stored == 0) throw std::runtime_error("stack is empty");
return stack[stored - 1];
}
[[nodiscard]] value_type& top() {
if(stored == 0) throw std::runtime_error("stack is empty");
return stack[stored - 1];
}
[[nodiscard]] size_t capability() const noexcept { return cap; }
[[nodiscard]] size_t size() const noexcept { return stored; }
private:
size_t cap, stored;
std::unique_ptr<value_type[]> stack;
};
计算。您保留了上次迭代中的值,而不是从堆栈中获取新值。还有多余的内存分配是不必要的,所以我删除了它。
op