C++返回栈上的数组（局部变量）问题探索

char* teststr() {
    char s[] = "hello"; 
    return s;
}

void main()
{
    char* str = teststr();
    char c1 = str[0]; //h
    char c2 = str[1]; //e
    char c3 = str[2]; //l
    char c4 = str[3]; //l
    char c5 = str[4]; //o
    char c6 = str[5]; //\0

    char* s2 = str;
    
    printf(str);
}

char* teststr() {
    char s[] = "hello"; //字符串变量
    return s; 
}

char* teststr2() {
    char* s = "hello"; //字符串常量
    return s;
}