1. 除以零的错误是未定义的。
示例代码#include <iostream>using namespace std;int main() { int x = 10, y = 0; int z = x / y; cout << "done" << endl;}
outputruntime error for divide by zero operation
2. trying to use uninitialized variable.
example code#include <iostream>using namespace std;int main() { bool x; if(x == true) cout << "true value"; else cout << "false value";}
outputfalse value (this may differ in different compilers)
3. trying to access null pointer values.
example code#include <iostream>using namespace std;int main() { int *ptr = null; cout << "the pointer value is: " << *ptr;}
outputruntime error for accessing null pointer values
4. trying to access null pointer values.
example code#include <iostream>using namespace std;int main() { int array[10]; for(int i = 0; i<=10; i++) { cout << array[i] << endl; }}
outputruntime error for accessing item out of bound.some compiler may return some arbitrary value, not return any error
5. 超出有符号整数的限制。
示例代码#include <iostream>using namespace std;int main() { int x = int_max; cout << "x + 1: " << x + 1;}
outputx + 1: -2147483648circulate to the minimum number of signed int
6. 尝试更改字符串字面值中的某些字符。
示例代码#include <iostream>using namespace std;int main() { char *str = "hello world"; str[2] = 'x'; cout << str;}
outputruntime error because we are trying to change the value of some constant variables.
以上就是在c和c++中的未定义行为的详细内容。