算术表达式求值演示 python代码
时间: 2023-12-01 16:40:21 浏览: 46
是Python中算术表达式求值的演示代码:
```python
# 定义变量x和y的值
x = 5
y = 3
# 计算表达式的值
result = (x + y) * (x - y)
# 输出结果
print(result)
```
在这个例子中,我们定义了变量x和y的值,然后计算了表达式`(x + y) * (x - y)`的值,并将结果存储在变量`result`中。最后,我们使用`print`函数输出了结果。
如果你想计算其他的算术表达式,只需要将表达式替换到代码中的相应位置即可。
相关问题
算术表达式求值演示 c++代码
以下是一个简单的C++代码演示算术表达式求值:\n\```++\#inclu <iostream>\#inclu <stack>\#inclu <string>\using namesp s;\n\i priority(char op) {\ if (p == '+' || op == '-') {\ retur 1;\ }\ els if (p == '*' || op == '/') {\ retur 2;\ }\ els {\ retur ;\ }\}\n\ub calcu(doub , doub b, char op) {\ switch (p) {\ cas '+':\ retur + b;\ cas '-':\ retur - b;\ cas '*':\ retur * b;\ cas '/':\ retur / b;\ defau\ retur ;\ }\}\n\ub evalu(string exp) {\ stack<doub> numStack;\ stack<char> opStack;\ for (i i = ; i < exp.length(); i++) {\ if (isdigi(exp[i])) {\ doub num = exp[i] - '';\ whi (i + 1 < exp.length() && isigi(exp[i + 1])) {\ num = num * 10 + (xp[i + 1] - '');\ i++;\ }\ numStack.push(num);\ }\ els if (xp[i] == '(') {\ opStack.push(exp[i]);\ }\ els if (xp[i] == ')') {\ whi (pStack.top() != '(') {\ char op = opStack.top();\ opStack.pop();\ doub b = numStack.top();\ numStack.pop();\ doub = numStack.top();\ numStack.pop();\ numStack.push(u(, b, op));\ }\ opStack.pop();\ }\ els if (xp[i] == '+' || exp[i] == '-' || exp[i] == '*' || exp[i] == '/') {\ whi (!pStack.empty() && priority(opStack.top()) >= priority(exp[i])) {\ char op = opStack.top();\ opStack.pop();\ doub b = numStack.top();\ numStack.pop();\ doub = numStack.top();\ numStack.pop();\ numStack.push(u(, b, op));\ }\ opStack.push(exp[i]);\ }\ }\ whi (!pStack.empty()) {\ char op = opStack.top();\ opStack.pop();\ doub b = numStack.top();\ numStack.pop();\ doub = numStack.top();\ numStack.pop();\ numStack.push(u(, b, op));\ }\ retur numStack.top();\}\n\i mai() {\ string exp = \2*(3+4)-5/2\";\ doub resu = evalu(exp);\ cou << \Th resu of \ << exp << \ is \ << resu << ;\ retur ;\}\```\n\
算术表达式求值演示数据结构代码
以下是一个算术表达式求值的演示代码,使用数据结构中的栈来实现:
```python
class Stack:
def __init__(self):
self.items = []
def is_empty(self):
return len(self.items) == 0
def push(self, item):
self.items.append(item)
def pop(self):
if not self.is_empty():
return self.items.pop()
def peek(self):
if not self.is_empty():
return self.items[-1]
def size(self):
return len(self.items)
def evaluate_expression(expression):
operators = {'+': 1, '-': 1, '*': 2, '/': 2}
operand_stack = Stack()
operator_stack = Stack()
for char in expression:
if char.isdigit():
operand_stack.push(int(char))
elif char in operators:
while (not operator_stack.is_empty() and
operators[char] <= operators[operator_stack.peek()]):
operand2 = operand_stack.pop()
operand1 = operand_stack.pop()
operator = operator_stack.pop()
result = perform_operation(operand1, operand2, operator)
operand_stack.push(result)
operator_stack.push(char)
while not operator_stack.is_empty():
operand2 = operand_stack.pop()
operand1 = operand_stack.pop()
operator = operator_stack.pop()
result = perform_operation(operand1, operand2, operator)
operand_stack.push(result)
return operand_stack.pop()
def perform_operation(operand1, operand2, operator):
if operator == '+':
return operand1 + operand2
elif operator == '-':
return operand1 - operand2
elif operator == '*':
return operand1 * operand2
elif operator == '/':
return operand1 / operand2
expression = "3+4*2-6/3"
result = evaluate_expression(expression)
print("Result:", result) # 输出:7
```