Second class exercise

One 、 Judgment questions

1. Overloaded functions can have default values and arguments , But pay attention to ambiguity .（T）

2. Functions with the same name can be distinguished by namespace （T）

3. Functions with the same name can be distinguished by namespace （T）

4. Symbolic constants must be initialized when they are defined .（T）

Two 、 Single topic selection

2-1
Namespace applies to ：（B）

A. Define the member function of the class outside the class
B. Avoid different functions 、 Name conflict of variable, etc
C. Speed up code execution
D. All the above answers are correct

2-2
If the local variable defined in the function has the same name as the variable in the namespace ,（B） Be hidden .

A. Variables in functions
B. Variables in namespace
C. Both variables
D. Neither of these variables

2-3
If used in the program using The command references multiple namespaces at the same time , And the same function exists in the namespace , Will appear ：（A）

A. Compile error
B. Grammar mistakes
C. Logic error
D. The error type cannot be determined

2-4
To specify which namespace the identifier belongs to , You need to add... Between the identifier and the namespace name ：（A）

A.::
B.->
C…
D.( )

2-5
If the function of the default parameter is declared as “ void fun(int a,int b=1,char c=‘a’,float d=3.2);”,
The correct way to call the following is （B ）.

A.fun();
B.fun(2,3);
C.fun(2, ,‘c’,3.14)
D.fun(int a=1);

3、 ... and 、 Completion

1.（6 branch ）A pointer allows us to pass potentially large amounts of data around at low cost: instead of copying the data we simply pass its address as a pointer value. The type of the pointer determines what can be done to the data through the pointer.

2.(8 branch ）Like a pointer, a reference is an alias for an object, is usually implemented to hold a machine address of an object, and does not impose performance overhead compared to pointers, but it differs from a pointer in that:You access a reference with exactly the same syntax as the name of an object. A reference always refers to the object to which it was initialized There is no “null reference,” and we may assume that a reference refers to an object.

3.（6 branch ）A reference is an alternative name for an object, an alias. The main use of references is for specifying arguments and return values for functions in general and for overloaded operators in particular.

Four 、 Fill in the blanks in the program

5-1
Use dynamic memory 1
fraction 10
author Zhang Dehui
Company Xi'an University of Posts and Telecommunications
Fill in the blanks to make the following procedures complete and run correctly .

#include
using namespace std;

int main ( )
{
double* pDouble = NULL; // initialized with null
pDouble =
new double
; // Request memory for the variable

char* pChar =
NULL
; // initialized with null
pChar = new char[20]; // Request memory for the array

cin>>*pDouble >>pChar; // Store value at allocated address
cout << *pDouble<<endl << pChar<<endl ;

delete pDouble; // free up the memory.

delete [] pChar
; // free the memory pointed to by pChar

return 0;
}

5、 ... and 、 Function questions

6-1 Area calculator （ function overloading ）

fraction 10
author He Zhenfeng
Company Fuzhou University
Implement an area calculator , It can calculate the area of a rectangle or cuboid .

Function interface definition ：
int area(int x, int y);
int area(int x, int y, int z);
The first function calculates the area of a rectangle , among x and y It's length and width . The second function calculates the surface area of the box ,x,y and z It's long , Width and height .

Sample referee test procedure ：
#include
#include
using namespace std;
int area(int,int);
int area(int,int,int);
int main()
{
int i, repeat, c, x, y, z;
cin>>repeat;
for(i=0;i<repeat;i++){
cin>>c;
if(c2){
cin>>x>>y;
cout<<area(x,y)<<endl;
}
if(c3){
cin>>x>>y>>z;
cout<<area(x,y,z)<<endl;
}
}
return 0;
}

/* Please fill in the answer here */
sample input ：
2
2 1 2
3 2 3 4
sample output ：
2
52

int area(int x,int y){
    
    return x*y;
}
int area(int x,int y,int z){
    
    return (x*y+x*z+z*y)*2;
}

6-2 Find the maximum and minimum

fraction 10
author Zhang Dehui
Company Xi'an University of Posts and Telecommunications
This question requests to realize a function f, We can find out 10 The maximum of integers max Minimum value min.

Function interface definition ：
Call this function in the main function as follows
f(a,10,max,min);
for example ： among a It's an array name ,max Used to save the maximum value ,min Used to save the minimum value .

Sample referee test procedure ：
#include
using namespace std;
/* The code you submit will be embedded here */

int main( )
{
int a[10];
int max,min,i;
for(i=0;i<10;i++){
cin>>a[i];
}
f(a,10,max,min);
cout<<"Max: "<<max<<endl;
cout<<"Min: "<<min<<endl;
return 0;
}
sample input ：
2 5 8 1 4 7 3 6 9 0
sample output ：
Max: 9
Min: 0

void f(int * a,int b,int &max,int &min)
{
    
    max = min = a[0];
    for(int i=1;i<10;i++)
    {
    
        if(max<a[i])
        {
    
            max = a[i];
        }
        if(min>a[i])
        {
    
            min = a[i];
        }
    }
}