C/C++ quizs

#include
#include
#include
#include
#include

using namespace std;

///Q1
class Special
{
private:
	int x;
	
public:
	Special()
	{
		cout << "constructor : This is special" << endl;
	}
	~Special()
	{
		cout << "~Special" << endl;
	}
	Special(const Special & special)
	{
		x = special.x;
		cout << "Copy constructor " <= 0);
}

//Q4 : 
void test_rand()
{

	srand((unsigned)time(0));
	for(int n=3; n>0; n--)
	{
		cout<< rand() << endl;
	}

}

//Q5: 
void test_pointer_arrary()
{
	char *pstr[] = {"welcome", "to", "China"};
	printf("%s : size= %d\n", pstr[0], sizeof(pstr)/sizeof(pstr[0]));
	printf("%s : size= %d\n", pstr[1], sizeof(pstr[1]));
}

//Q6: test what will be printed 
void test_out()
{
	int a, b;
	unsigned int c,d;
	a = -20;
	c = 19.5;
	d = (a+c) ? c : a;
	b = (a+c > 0) ? a : c;
	if(a+c > 0)
	{
		printf("a+c > 0\n");
	}
	printf("d = %d\n",d);
	printf("b = %d\n",b); 
	printf("a+c = %d\n",a+c);
	printf("c = %d\n",c); 
/**
Answer
a+c > 0
d = 19
b = -20
a+c = -1
c = 19
**/
}

//Q7: test structure on 32 bits system
void test_struct()
{
	struct AAA
	{
		char a[5];
		int b;
		short int c;
	};
	struct BBB
	{
		char *d;
		short int c;
		struct AAA f;
		char g;
	};
	printf("sizeof(AAA) = %d\n", sizeof(struct AAA)); //16
	printf("sizeof(BBB) = %d\n", sizeof(struct BBB)); //28
}


//Q8: quiz on reference of c++
//what will be printed by this function
void tough_one()
{
	int x=0;
	int &y = x ;
	int z = 3;
	++x;
	++y;
	y=z;
	cout <<"y:" << y << ";x:" << x <<";z:" << z << endl;
	z += 5; // this operation will not make variable y changed.
	cout <<"y:" << y << ";x:" << x <<";z:" << z << endl;
	++x;
	y=x;
	cout <<"y:" << y << ";x:" << x <<";z:" << z << endl;
	x += 5;
	cout <<"y:" << y << ";x:" << x <<";z:" << z << endl;
	++y;
	cout <<"y:" << y << ";x:" << x <<";z:" << z << endl;
	
	/**** Answer
y:3;x:3;z:3
y:3;x:3;z:8
y:4;x:4;z:8
y:9;x:9;z:8
y:10;x:10;z:8
	***/
}

//Q9:  what's the *(*ptr) mean ? 


//Q10:
void quiz_ten()
{
	int array[10] = {1,2,3,4,5,6,7,8,9,10};
	int *m = array;
	int *m1 = m;
	m1 = m1 + 1;
	int *n = &array[5];
	printf("n-m = %ld\n", n-m);
	printf("m1-m = %ld\n", m1-m);
	printf("*m1 = %d\n", *m1);
	
/****
n-m = 5
m1-m = 1
*m1 = 2
**/	
}

//Q11: what's the correct implmetation of the swap function;
void swap(int *p1, int *p2)
{
/* this was not working , only chage the address
	int *p;
	p = p1;
	p1 = p2;
	p2 = p;
	*/
	// this can be working 
	int p;
	p = *p1;
	*p1 = *p2;
	*p2 = p;
}

//Q12
void quiz_twelve()
{
	int a[][3] = {{20,19,18}, {33,34,45}, {66,37,18}, {1,2,3} };
	int *p = a[1]+5;
	printf("*p = %d\n", *p);
	//*p = 18
}

//Q13
void quiz_thirteen()
{
	char a[] = "Language", b[] = "Programe";
	char *p1, *p2;
	p1 = a;
	p2 = b;
	for (int k = 0 ; k<=7; k++)
	{
		if (*(p1+k) == *(p2+k))
		{
			printf("%c",*(p1+k));
		}
	}
	printf("\n");
	//gae
}
//Q14 : in small-endian CPU, what's the output.
void quiz_fourteen()
{
	typedef struct strBitData
	{
		unsigned int ulData1:2;
		unsigned int ulData2:12;
		unsigned int :2;
	}strBitData;
	strBitData stData;
	unsigned int *pOutputData;
	memset((void*)&stData, 0, sizeof(strBitData));
	stData.ulData1 = 0x7;
	stData.ulData2 = 0x010;
	pOutputData = (unsigned int *) &stData;
	unsigned char *p = (unsigned char *) &stData;
	for (int i = 0; i<2; i++)
	{
		printf("0x%x\n", *(p+i));
	}
	printf("0x%x\n", *pOutputData);
	printf("0x%x\n", stData.ulData1);
	printf("0x%x\n", stData.ulData2);
	/***
0x43
0x0
0x43
0x3
0x10
	**/
}


//Q15:
//how many places with dynamic sapce allocated when the function executed.

static vector g_vector(2);
void quiz_fifteen()
{
	string my_string = "This is string";
	vector l_vector;
	g_vector.push_back(1);
	l_vector.push_back(10);
	cout << "at(0): " << g_vector.at(0) << "\t max_size :" << g_vector.max_size() << endl;
	cout << "global vec.size(): " << g_vector.size() << "\t vec.capacity(): " << g_vector.capacity() << endl;
	cout << "local  vec.size(): " << l_vector.size() << "\t vec.capacity(): " << l_vector.capacity() << endl;
}

/*
at(0): 0
global vec.size(): 3	 vec.capacity(): 4
local  vec.size(): 1	 vec.capacity(): 1
**/

//Q16: 
void quiz_sixteen()
{
	vector  l_vec_obj;
	Special special;
	l_vec_obj.push_back(special);
	l_vec_obj.pop_back();
/****
constructor : This is special
Copy constructor 
~Special
~Special
****/	
}

//Q17
class Base
{
public:
	virtual void func();
	int a;
};

class Base1
{
public:
	virtual void func1();
	int a;
};

class DeriveA : public Base
{
public:
	virtual void func();
};

class DeriveB : public Base, public Base1
{

};

class DeriveC : virtual public Base
{

};

class DeriveD : virtual public Base, virtual public Base1
{

};
//on 64 bits system , tips ,sizeof(pointer) = 8

void quiz_seventeen()
{
	cout << "sizeof(Base)" << sizeof(Base) << endl;
	cout << "sizeof(DeriveA)" << sizeof(DeriveA) << endl;
	cout << "sizeof(DeriveB)" << sizeof(DeriveB) << endl;
	cout << "sizeof(DeriveC)" << sizeof(DeriveC) << endl;
	cout << "sizeof(DeriveD)" << sizeof(DeriveD) << endl;	
/***
sizeof(Base)16
sizeof(DeriveA)16
sizeof(DeriveB)32
sizeof(DeriveC)24
sizeof(DeriveD)40
*****/	
}

int main()
{
	// 1) test: printf all the string with end char'\0'
	const char *p = "abc";
	char pAarry[] = {'a','b','c'};
	printf("%s, %s\n",p,pAarry);
	// 2) test 
	int *pInt = getNumber();
	int a = 77;
	printf("%d\n", *pInt);
	
	// 3) 
	//Special spcail = Special(10);
	//spcail.printf_x();
	
	//4) 
	//test_execute_times();
	test_rand();
	test_pointer_arrary();
	tough_one();
	test_out();
	test_struct();
	quiz_ten();
	//Q11:
	int t11a = 10;
	int t11b = 20;
	swap(&t11a, &t11b);
	printf("a = %d, b = %d\n", t11a, t11b);
	quiz_twelve();
	quiz_thirteen();
	quiz_fourteen();
	quiz_fifteen();
	quiz_sixteen();
	quiz_seventeen();
	return 0;
}

//Q9:  what's the *(*ptr) mean ?