Python新手求助：计算器代码触发NameError变量未定义错误

错误原因 #

当输入numbercount=3时，代码前半段的条件判断仅在numbercount==2时会给mathtype赋值，而numbercount==3的mathtype赋值逻辑在后续位置，导致程序执行到if mathtype ==1语句时，mathtype变量尚未定义，触发NameError: name 'mathtype' is not defined。

修复后的代码 #

print("Calculator!!!")
loop = 1
# basic inputs
numbercount = int(input("How many numbers are you doing math with? max is 3: "))

while loop == 1:
    if numbercount == 1:
        print("minimum numbers are 2")
    elif numbercount == 2:
        mathtype = int(input("1. Addition\n2. Subtraction\n3. Multiplication\n4. Division\n"))
        if mathtype == 1:
            print("format as\na = [number]\nb = [number]\n")
            a = int(input("a = "))
            b = int(input("b = "))
            c = a + b
            print("Your answer is: ", c)
        elif mathtype == 2:
            print("format as\na = [number]\nb = [number]\n")
            a = int(input("a = "))
            b = int(input("b = "))
            c = a - b
            print("Your answer is: ", c)
        elif mathtype == 3:
            print("format as\na = [number]\nb = [number]\n")
            a = int(input("a = "))
            b = int(input("b = "))
            c = a * b
            print("Your answer is: ", c)
        elif mathtype == 4:
            print("format as\na = [number]\nb = [number]\n")
            a = int(input("a = "))
            b = int(input("b = "))
            c = a / b
            print("Your answer is: ", c)
        else:
            print("Invalid choice, try again")
    elif numbercount == 3:
        mathtype = int(input("1. Addition\n2. Subtraction\n3. Multiplication\n4. Division\n"))
        if mathtype == 1:
            print("format as\na = [number]\nb = [number]\nc = [number]\n")
            a = int(input("a = "))
            b = int(input("b = "))
            c = int(input("c = "))
            d = a + b + c
            print("Your answer is: ", d)
        elif mathtype == 2:
            print("format as\na = [number]\nb = [number]\nc = [number]\n")
            a = int(input("a = "))
            b = int(input("b = "))
            c = int(input("c = "))
            d = a - b - c
            print("Your answer is: ", d)
        elif mathtype == 3:
            print("format as\na = [number]\nb = [number]\nc = [number]\n")
            a = int(input("a = "))
            b = int(input("b = "))
            c = int(input("c = "))
            d = a * b * c
            print("Your answer is: ", d)
        elif mathtype == 4:
            print("format as\na = [number]\nb = [number]\nc = [number]\n")
            a = int(input("a = "))
            b = int(input("b = "))
            c = int(input("c = "))
            d = a / b / c
            print("Your answer is: ", d)
        else:
            print("Invalid choice, try again")
    else:
        print("Max numbers is 3")
    
    # 添加退出循环选项，避免无限循环
    continue_loop = input("Do you want to calculate again? (y/n): ").lower()
    if continue_loop != 'y':
        loop = 0

额外修复点 #

1. 修正拼写错误：awnser改为answer，Multiplcation改为Multiplication
2. 修复3个数计算时的输出错误：原本输出输入变量c，改为输出计算结果d
3. 添加循环终止逻辑，避免程序无限运行
4. 调整代码缩进，让不同numbercount的逻辑块完全分离，避免交叉执行问题

内容的提问来源于stack exchange，提问作者Yodeling_Tornado