Question

这是我的代码：

#include <iostream>
#include <typeinfo>

using namespace std;


int main() {
    const int size = 10;
    char test[size];
    char test2[size];

    cout << "the size of test is " << sizeof(test) << endl;

    cout << "input a sentence:" << endl;
    cin.getline(test, 50);

    cout << "your input is: " << test << endl;
    cout << "the size of test is " << sizeof(test) << endl;

    cout << "-----stop-----" << endl;
    return 0;

}

我使用 MinGw-w64 3.1 在Clion进行了测试，结果如下：

the size of test is 10
input a sentence:
this is a very long sentence
this is a very long sentence
your input is: this is a very long sentence
the size of test is 10
-----stop-----

Process finished with exit code -1073741819 (0xC0000005)

在我完成所有输出之前它没有停止。我试图读取阵列测试的那一刻不应该停止吗？毕竟，我声称尺寸为10，但试图读取尺寸50。

然后我在Ubuntu下使用 gcc 5.4.0 测试了它，它没有发出任何错误消息！我想知道它为什么不停止？

Answer 1

因为你（非）幸运！

这是我得到的：

from turtle import Turtle, Screen

TEXT = "Penny for your thoughts"  # arbitrary text
POSITION = (150, 150)  # arbitrary position

FONT_SIZE = 36  # arbitrary font size
FONT = ('Arial', FONT_SIZE, 'normal')

X, Y = 0, 1

def box(turtle, lower_left, upper_right):
    """ same as above example """

screen = Screen()

marker = Turtle(visible=False)
marker.penup()
marker.speed('fastest')
marker.fillcolor('pink')
marker.setx(screen.window_width() + 1000)

start = marker.position()
marker.write(TEXT, align='center', move=True, font=FONT)
end = marker.position()
marker.undo()  # clean up after ourselves

marker.speed('normal')
marker.goto(POSITION)

# Since it's centered, the end[X] represents 1/2 the width
half_width = end[X] - start[X]
marker.begin_fill()
box(marker, (POSITION[X] - half_width, POSITION[Y]), (POSITION[X] + half_width, POSITION[Y] + FONT_SIZE))
marker.end_fill()

marker.write(TEXT, align='center', font=FONT)

screen.exitonclick()

您目击的是未定义的行为，这意味着它未定义代码执行时会发生什么。

为什么cin.get（char，int）不会溢出？

1 个答案: