Embedded written test/interview typical questions

From: http://blog.163.com/softwaredep@126/blog/static/474112722007102593541438/

 

Output

Char S1 [] = "2 kgames ";

Char * S2 [] = {"2 kgames "};

Char S3 [20] = "2 kgames ";

Sizeof (S1) =?

Sizeof (S2) =?

Sizeof (S3) =?

Strlen (S1) =?

Strlen (S3) =?

<Answer: 8 4 20 7 7

 

2. Output

Class

{

Public:

A () {P ();}

~ A () {P ();}

Virtual void P () {q ();}

Virtual void Q () {cout <''a ''}

};

Class B: public

{

Public:

B () {P ();}

~ B () {P ();}

Void Q () {cout <'B ''}

};

Int main ()

{

A * P = new B;

Delete P;

}

Answer: ABA

 

3. Use a c expression to determine whether a number is the N power of 2.

Answer: x = (x ^ (~ 0x0) + 1) & X)

 

4. Write a high-performance function to multiply an int by 9

Answer:

Int multiply_9 (int)

{

Return (A <3) + );

}

 

5. Write a C function. If the processor is big_endian, 0 is returned. If the processor is little_endian, 1 is returned.

Answer:

Int checkcpu ()

{

Union W

{

Int;

Char B;

} C;

C. A = 1;

Return (C. B = 1 );

}

 

6. INT (* f) (INT, INT) (INT) What is f here?

Answer: F is a pointer pointing to a function with the (INT, INT) parameter and the return value is a pointer.

The returned Pointer Points to a function with the (INT) parameter and the return value is int.

My written test II: Cisco

1.

Typedef struct

{

Char data [10];

} T1;

 

Typedef struct

{

T1 * P;

Char data [0];

} T2;

Sizeof (T2) =?

 

Answer: 4

 

2. An array containing n elements. The value range of the array is 1 ~ N-1 to find the repeated value.

Answer:

Int array [N];

Int findrepeat (void)

{

Int flag [N] = {0 };

Int I;

For (I = 0; I less than N; I ++) // the error message returned when the system of this forum is abnormal due to a problem in the system of this forum.

{

If (flag [array [I] = 1)

Return array [I];

Else

Flag [array [I] = 1;

}

}

3. Which of the following cannot be translated?

().

Void T ()

{

Const int n= 100;

Int A [n];

A [2] = 42;

}

(B ).

Void T ()

{

* (Int * const) 0x23567890) = 5;

}

 

(C ).

Char * FUC (void)

{

Char A [4];

Strcpy (a, "ABCD ");

Return;

}

 

Answer: ABC can all be compiled.

My written test article 3: Trend Micro

1. Incorrect search

(1) void test (const int V)

{

Int * P;

P = V;

}

Answer: The non-const pointer cannot be directed to the const variable. It should be: const int * P;

 

(2) void test (const Int & V)

{

Const Int & P;

P = V;

}

Answer: The reference must be initialized during definition. It should be: const Int & P = V;

 

2. programming questions: Flip the linked list.

Answer:

Typedef struct Node

{

Int value;

Struct node * next;

} Slink;

 

Slink * reverselink (slink * H)

{

Slink * Pre, * cur, * next;

Pre = NULL;

Cur = h;

Next = cur-> next;

While (next)

{

Cur-> next = pre;

Pre = cur;

Cur = next;

Next = Next-> next;

}

Return cur;

}

 

3. Write output results

Class

{

Public:

A ()

{

F (0 );

}

Virtual void F (int n)

{

Cout <"A0:" <}

Virtual void F (int n) const

{

Cout <"A1:" <}

Virtual void F (char * s)

{

Cout <"A2:" <}

};

Class B: public

{

Public:

Void F (int n)

{

Cout <"B0:" <}

Void F (char * s)

{

Cout <"B1: <}

};

Int main ()

{

A * P;

Const A * CP;

B;

P = & B;

P-> F (1 );

P-> F ("test ");

A (). F (2 );

CP = & B;

CP-> F (2 );

}

Answer:

A0: 0

B0: 1

B1: Test

A0: 0

A0: 2

A1: 2

 

4. What is the transmission distance of UTP (unshielded twisted pair wires?

Answer: 100 m

 

The subnet mask of 5.176.68.160.0/22 is:

Answer: 255.255.252.0

My Written Test 4: Pioneer Shang Tai

1. Which of the following statements is true:

A. char * const S = "hello ";

* S = ''' w ''''

B. char * const S = "hello ";

S = "world ";

C. Const char * s = "hello ";

* S = ''' w ''''

D. Const char * s = "hello ";

S = "world ";

Answer: d

 

2. Which of the following statements is true:

A. char * const S = "hello ";

* S = ''' w ''''

B. char * const S = "hello ";

S = "world ";

C. Char s [] = "hello ";

* S = ''' w ''''

D. Char s [] = "hello ";

S = "world ";

Answer: c

 

3. Write the program output result:

Char T [] = "abcdefghijklmno ";

T [12] = ''/0'' // there shouldn't be so many single quotes

Int I = 0;

While (T [++ I]! = ''/0'') // here is also

{

Printf ("% C", t [I ++]);

}

Answer: bdfhjln

My Test 5-Zhan Xun

1. Calculate the maximum public string of two strings programmatically.

Answer:

# Include "stdio. H"

# Include "string. H"

 

/* Function: calculate the maximum public string of two strings */

Void commonstr (char * str1, char * str2)

{

Char * S1, * S2;

Int I, j, k; // I -- maximum length of a Public String

Int len1; // J -- start position of the substring S2

Int len2; // K -- start position of the substring S1

Int P;

Len1 = strlen (str1 );

Len2 = strlen (str2 );

If (len1
{

S1 = str2;

S2 = str1;

Len2 = len1;

}

Else

{

S1 = str1;

S2 = str2;

}

For (I = len2; I> 0; I --) // start from the largest

{

For (j = 0; j + I <= len2; j ++)

{

For (k = 0; k + I <= len1; k ++)

{

P = 0;

While (S1 [K + P] = S2 [J + P])

{

P ++;

}

If (P> = I)

{

For (P = 0; P is smaller than I; P ++)

Printf ("% C", S1 [K + P]);

Printf ("/N ");

Return;

}

}

}

}

}

Int main (void)

{

Char * S1 = "worlld ";

Char * S2 = "Hello, cjw ";

Commonstr (S1, S2 );

Return 0;

}

 

2. Calculate the number of 1 bytes.

Method 1:

Int num_1 (char data)

{

Int I, J;

Int sum = 0;

J = 1;

For (I = 0; I <8; I ++)

{

J = 1 <
If (Data & J)

Sum ++;

}

Return sum;

}

Method 2:

Unsigned int findoneinnumber_02 (unsigned char X)

{

Unsigned int N;

For (n = 0; X; n ++)

X & = X-1;

Return N;

}