计科：week11 自编选择题

[wujr5]

week11 Experiment 5.5

自编选择题

由于本周没有实验任务，根据老师要求，添加小小的课后练习。很轻松，很简单，也很有趣。

要求

1. 每个人设计三道选择题。
2. 每一道选择题覆盖的知识点不限，但不能太简单，一看就懂的那种就十分不建议。
3. 最好是C++语言中难以理解的知识点，或者容易忽略的重点。
4. 除了问题以外，你还有为你的问题准备答案，以及相关解释。
5. 周五上课随机抽取部分同学的选择题，让大家一起做，然后由作者讲解，其他同学可以质疑并提问。
6. 请使用英文。

模板

0 简介

你的姓名学号
balabala你出题的初衷诸如此类

1 题目

1.1 题目1

balabala题目内容

1.2 题目2

balabala题目内容

1.3 题目3

balabala题目内容

2 答案及解析

2.1 题目1答案及解析

balabala题目答案及解析

2.2 题目2答案及解析

balabala题目答案及解析

2.3 题目3答案及解析

balabala题目答案及解析

提交

提交到如下文件夹。

命名格式

cs_cpp_学号_姓名_exp5.5.pdf

Deadline

12月3日 21：00

最后

请把你的题目部分添加到本github下面的评论区域，就像你的期中总结一样。

格式：(注意加粗和空行，为了好看些~)

学号：1555xxxx，姓名：张三

题目1：
balabala题目内容

题目2：
balabala题目内容

题目3：
balabala题目内容

[wujr5]

Example

学号：1555xxxx，姓名：张三

题目1：

1. Is TA a homesome boy ? Please choose the right answer.
A. Yes, he is. 
B. Yes, he very is. 
C. Yes, he very very is. 
D. Yes, he very very very is.

题目2：
balabala题目内容

题目3：
balabala题目内容

[yzq986]

学号：15336226，姓名：叶子卿

题目1：

1. What's the output of following program:

int a;
void print(int x) {
    if (x > 5) return;
    cout << x << ' ';
    print(x ++);
}
int main() {
    a = 0;
    print(a);
    return 0;
}

A. 0 1 2 3 4 5 6
B. 0 1 2 3 4 5
C. 1 2 3 4 5
D. endless loop

题目2：
2. What's the output of following program:

int a;
void print(int x) {
    if (x > 5) return;
    cout << a << ' ';
    print(a ++);
}
int main() {
    a = 0;
    print(a);

    return 0;
}

A. 0 1 2 3 4 5 6
B. 0 1 2 3 4 5
C. 1 2 3 4 5
D. endless loop

题目3：
3. What's the output of following program:

int a;
void print(int x) {
    if (x > 5) return;
    cout << a << ' ';
    print(++ a);
}

int main() {
    a = 0;
    print(a);

    for(;;);
    return 0;
}

A. 0 1 2 3 4 5 6
B. 0 1 2 3 4 5
C. 1 2 3 4 5
D. endless loop

[SchroDeCat]

学号：15336237，姓名：张丰学

题目1
What is true about the following code:

int main() {
    string a,b;
    cin >> a;
    getline(cin,b);
    getline(cin,b);
    return 0;
}

A. if the input is “1 2”, a is “1”, b is “ 2”;
B. if the input is “1 2”, a is “1”, b is “2”;
C. if the input is “1” in the first line and “2” in the second line, a is “1”, b is “ 2”;
D. if the input is “1” in the first line and “2” in the second line, a is “1”, b is “2”;

题目2
What is true about the following code:

int main() {
    const double PI = 3.1415926;
    cout << fixed << setprecision(2);
    cout << PI << endl;
    cout << setw(8);
    cout << PI << endl;
    cout << PI << endl;
    return 0;
}

A. the output are “3.1415926” in three different lines;
B. the output are “3.14” in three different lines;
C. the output are “3.14” in the first line and “ 3.14” in the following two lines.
D. None of the above

题目3
What is true about the following code:

int main() {
    string a = "100";
    string b = "200";
    int c, d;
    stringstream mid;
    mid << a;
    mid >> c;
    mid << b;
    mid >> d;
    cout << a / b << endl;
    return 0;
}

A. The code can compile and run well
B. The output will be 0.5 if ” cout << a / b << endl;” is changed into “”cout << c / d << endl;”
C. The output will be 0.5 if ” cout << a / b << endl;” is changed into “”cout << (double)c / d << endl;”
D. None of the above

[SgLy]

学号：15336251，姓名：郑树诚

---

Problem 1: What will happen to the following code?

#include <iostream>
using namespace std;

int main() {
    {
        int a;
        a = 5;
    }
    cout << a << endl;
    return 0;
}

A. Encounter a compilation Error;
B. Output: 5;
C. Encounter a run-time Error;
D. Output: 0.

---

Problem 2: What will happen to the following code?

#include <iostream>
using namespace std;

int main() {
    int b = 0;
    b = b++;
    cout << b << endl;
    return 0;
}

A. Encounter a compilation Error;
B. Output: 1;
C. Encounter a run-time Error;
D. Output: 0.

---

Problem 3: What will happen to the following code?

#include <iostream>
#include <climits>
using namespace std;

int main() {
    int a;
    a = INT_MAX + 1;
    cout << a << endl;
    return 0;
}

A. Output: 2147483648;
B. Output: -2147483648;
C. Encounter a run-time Error;
D. Output: -1.

Hint: pow(2, 31) == 2147483648
      INT_MAX == 2147483647

[EtherCS]

学号：15336242，姓名：张舰廷

题目1
What is true about the following code:

int main() {
int a = 3;
cout << a && true;
cout << " ";
cout << (a && true) << endl;
return 0;
}
A、1 1；
B、3 1；
C、1 0；
D、compile error

题目2
What is true about the following code:

int qqb(int a = 1, int b = 2, int c) {
return a + b + c;
}
int main() {
int x;
x = qqb(10, 5);
cout << x << endl;
return 0;
}

A、15；
B、16；
C、17；
D、compile error

题目3
What is true about the following code:

int main() {
int x = 0, y1, y2, y3, y4;
y1 = (x++, x) ? 1 : 0;
x = 0;
y2 = (++x, x) ? 1 : 0;
x = 0;
y3 = (x, ++x) ? 1 : 0;
x = 0;
y4 = (x, x++) ? 1 : 0;
cout << y1 << " " << y2 << " " << y3 << " " << y4 << endl;
return 0;
}
A、1 1 1 1；
B、0 1 1 1；
C、1 1 1 0；
D、0 1 1 0；

[zhuzq5]

学号：15336267 姓名：朱志强
题目1：what’s the output of the following program？
#include
using namespace std;
int main() {
int a = 0;
int b = a ++;
int c = ++ a;
cout << b <<" "<< c;
}
A.1 1
B.0 1
C.1 0
D.0 2
题目2：what’s the output of the following program？
#include
using namespace std;
int s (int& b) {
b ++;
return b;
}
int main() {
int b = 1;
cout << s (b);
cout << " " << b;
}
A.1 1
B.1 2
C.2 2
D.None of above
题目3：what’s the output of the following program？
#include
using namespace std;
int main () {
bool s = -1;
if (s == 1) {
cout << "Hello World!";
}
else cout << "Error";
}
A.Hello World！
B.Error
C.Compile error
D.Noting

[no553216989]

学号：15336228 姓名：于博洋

题目1

1.What is the output of the following program
#include
using namespace std;
int main(){
int i=1;
cout << i++ + i++ << endl;
}

a.3
b.4
c.5
d.6

题目2
2.What is the output of the following program
#include
using namespace std;
int main(){
int i=1;
cout << ++i + ++i << endl;
}
a.3
b.4
c.5
d.6

题目3
3.What is the output of the following program
#include
using namespace std;
int main(){
int i=1;
cout << ++i + ++i + ++i<< endl;
}
a.6
b.8
c.10
d.12

[HELLKING66666]

学号：15336257， 姓名：钟晓庆

---

题目1：

1. What's the output of following program:

#include <iostream>
#include <string>
#include <sstream>
using namespace std;

int main() {
    string s1 = "5  complete";
    istringstream s2(s1);
    int m;
    s2 >> m;
    cout << m << endl;
return 0;
}

A. Encounter a compilation Error.
B. Output: 5.
C. Encounter a run-time Error.
D. Output: 5 complete.

题目2：
2. How many times is letter ‘a’ be printed? :

#include <iostream>
using namespace std;

int main()  {
    int i = 0;
    for( i; i < 10; i++) {
        }
    cout << “a” << endl;

A: 10.
B: Compiler Error.
C:Runtime Error.
D:1.

题目3：
3. What’s the output of the following code? :

#include <iostream>
using namespace std;

int main() {
int n = 1;
while(n--) {
        cout << n << “ ”;
}
return 0;
}

A: 1 0.
B: 0.
C: Nothing
D: Compiler Error.

[AK323]

学号：15337020， 姓名：施志雄

题目1
What is the value in count after the following loop is executed?
int count = 0;
do
{
cout << "Welcome to C++";
} while (count++ < 9);
cout << count;
A. 8
B. 9
C. 10
D. 11
题目2
int number = 25;
int i;
bool isPrime = true;
for (i = 2; i < number && isPrime; i++) 
{
   if (number % i == 0)
   {
     isPrime = false;
   }
}
cout << "i is " << i << " isPrime is " << isPrime << endl;
A.i is 5 isPrime is 1
B. i is 5 isPrime is 0
C. i is 6 isPrime is 1
D. i is 6 isPrime is 0
题目3
What is the output of the following program?

#include < iostream >
using namespace std;
int main()
{
   int a = 5;
   float b;
   cout << sizeof(++a + b);
   cout << a;
   return 0;
}
A. 2 6
B. 4 6
C. 2 5
D. 4 5

[YxMa666]

姓名：马玉玺　　　学号：15337016
1题目
1.1题目
What is the output of the following code?
double a[3] ={1.1,2.2,3.3};
cout<<a[0]<<” “<<a[1]<<” “<<a[2]<<endl;
a[1] =a[2];
cout<<a[0] <<” “<<a[1] <<” “<<a[2] <<endl;

1.2题目
What is the output of the following code?
Int i, temp[10];
For (i=0;i<10;i++)
Temp[i]=2*i;
For (i=0;i<10;i++)
cout<<temp[i]<<” “;
Cout<<endl;
For (i=0;i<10;i=i+2)
Cout<<temp[i]<<”＂；
1.3题目
What is the output of the following code?
int count=3;
while （count-->0）
cout<<count<<" ";

[MattMu]

学号：15337017 姓名：牟者斌

problem1

What is the output of the following program?

#include <iostream>
 using namespace std;
 void addprint()
 {
   static int s = 1;
   s++;
   cout << s;
}
int main()
{
   addprint();
   addprint();
   addprint();
   return 0;
}

A. 234
B. 111
C. 235
D. 123

problem2

What is the output of the following program?

#include <iostream>
using namespace std;
int main() {
  int a = 5;
  double b;
  cout << sizeof(++a + b);
  cout << a;
  return 0;
}

A. 2 6
B. 4 6
C. 2 5
D. 4 5
E. None of mentioned

problem3

What is y after the following statement is executed?

int x = 3; int y = 4;
if (( x ) || ( x > 3))
 switch (x + 3) {
  case 6: y = 0;
  case 7: y = 1;
  default: y += 1;
}
y = y++ + ++y;

A. 2
B. 4
C. 6
D. 8

[Icenowy]

0 简介

姓名:郑兴达
学号: 15336253

1 题目

1.1 题目 1

Which command can compile test.cpp and get a test.exe debuggable with GDB?
A. g++ -DDEBUG test.cpp -o test.exe
B. g++ test.cpp -g -o test.exe
C. gcc test.cpp -g -o test.exe
D. gdb test.cpp -o test.exe

1.2 题目 2

If I want to break before outputing variable out in the program shown below, what GDB command
should I use?

01:#include <iostream>
02:using namespace std;
03:
04:int main()
05:{
06:int out = 10;
07:out *= 20;
08:cout << out << endl;
09:return 0;
10:}

A.bt 8
B.b 8
C.cont
D.set args 8

1.3 题目 3

The source code of test.cpp (compiled into test.exe) is shown below:

#include <iostream>
using namespace std;
int main()
{
cout << "a" << endl;
cerr << "b" << endl;
}
return 0;

If I run D:\CS-Basic> test.exe > a.txt, What will occur?
A. Nothing printed, but the content of a.txt is “ab” (without “”).
B. “a” is printed, the content of a.txt is “b” (without “”).
C. “b” is printed, the content of a.txt is “a” (without “”).
D. “ab” is printed, nothing's in a.txt.

[yyh15336238]

学号：15336238 ， 姓名：张皓宇
题目1：
Problem 1 How many times will 'Hello' and 'World' be printed respectively?
#include
using namespace std;
void print (string, int);
double count (int a, int b = 3, int c = 6) {
double count = a + b + c;
return count;
}
void swap (int a, int b) {
int temp = a;
a = b;
b = temp;
}
int main() {
int a = 4;
int b = 7;
print ("Hello", 2);
swap (a, b);
print ("World", a);
return 0;
}
int a;
void print (string ch, int n) {
if (n == 4)
return;
n = count(a, 0);
n++;
for (int i = 0; i < n; i++)
cout << ch << endl;
}
A.7,12.
B.7,5.
C.7,0.
D.7,7.

题目2：
Problem2 Which is the correct output?
#include
using namespace std;
double a (int a,int b = 1,int c = 2) {
double q = a + b + c;
cout << q << " ";
}

int main() {
cout << a(4, 2) << " ";
cout << a (4, 3, '2') << " ";
}
A.8 8 9 9.
B.8 0 9 0.
C.8 0 57 0.
D.compile error.

题目3：
Problem3 To satisfy output Champion1234,what is the value of x and y,and the value of strlen(a) at last?
#include
#include
using namespace std;
int main() {
char a[] = "Champion12 34";
memmove (a+x, a+y, strlen(a));
cout << a << " ";
cout << strlen(a);
return 0;
}
A.11 12 12.
B.12 11 13.
C 10 11 12.
D.11 10 13.

[littleicemelon]

学号：15338259 姓名：周俊澎
题目1：what is i after the following for loop?
int y = 0;
for (int i = 0; i < 10; ++i) {
y += i;}
A. 9
B. 10
C.11
D.undefined
题目2：pow(4.0, 1/2)returns
A. 0
B. 1
C. 2
D. 3
题目3：What is the output of the following code:

int list[] = {1, 2, 3, 4, 5, 6};

for (int i = 1; i < 6; i++)
  list[i] = list[i - 1];

for (int i = 0; i < 6; i++)
  cout << list[i] << " ";

A. 1 2 3 4 5 6
B. 2 3 4 5 6 6
C. 2 3 4 5 6 1
D. 1 1 1 1 1 1

answer：DBD