C + + Primer eighth post-lesson programming questions

1. Write a function that normally accepts a parameter (the address of the string) and prints the string. However, if the second argument (int type) is supplied, and the argument is not 0, the number of times the function prints the string will be the number of times the function is called (note that the number of times the string is printed is not equal to the value of the second parameter, but is equal to the number of times the function was called). Yes, it's a very ridiculous function, but it letsreaders can use some of the techniques described in this chapter. Use this function in a simple program to demonstratehow the function works. Code:

#include <iostream>using namespace std;void Show (const char * A, int b=0); void Show (const char * A, int b) {    Stati c int uses = 0;    int lim = ++uses;    cout << "First" << uses << "call. \ n";    if (b==0)        lim = 1;    for (int i=0; i<lim; i++)        cout <<a<<endl;} int main () {    int i;    const char * p = "Hello world\n";    cout << "Number of input function calls:";    Cin >> I;    while (i>=0)    {        cout << "parameter n is:" <<i;        Show (P, i);        i--;    }    cout << "Default n is 0:";    Show (p);    return 0;}    

Operation Result:

2.The candybar structure is full of 3 members. The first member stores the brand name of the candy bar;the second member stores the weight of the candy bar (may have decimals); The third member stores Candy barof calories (integers). Please write a program that uses a function like this, which is about to CandyBar, char pointers, double and int as arguments, and the last 3 values to set the corresponding structuremembers. The default values for the last 3 parameters are "Millennium Munch", 2.85, and 350, respectively. In addition,The program also contains a function that takes a reference to CandyBar as a parameter and displays the contents of the structure. please use const as much as possible.Code

#include <iostream> #include <cstring>using namespace std;const int max=60;struct candybar{Char Brand[max];    Double weight; int energy;}; void Init (CandyBar & CB, const char *BR = "Millennium Munch", double we = 2.85, int ca =); void Displa    Y (const CandyBar & CB); int main () {CandyBar candybar;    cout << "Default candybar is:" <<endl;    Init (CandyBar);    Display (CandyBar);    Char Newbrand[max];    Double newweight;    int newenergy;    cout << "Please enter new CandyBar data:" <<endl;    cout << "Brand:";    Cin.get (Newbrand, MAX);    cout << "Weight:";    Cin >> Newweight;    cout << "energy:";    Cin >> Newenergy;    Init (CandyBar, Newbrand, Newweight, Newenergy);    Display (CandyBar); return 0;}    void Init (CandyBar &cb,const char *br, double we, int CA) {strcpy (Cb.brand, BR);    Cb.weight = we; Cb.energy = CA;}    void display (const candybar &AMP;CB) {cout << "new candybar: \ n"; cout << "Brand:" << cb.brand<<endl;    cout << "Weight:" <<cb.weight<<endl; cout << "energy:" &LT;&LT;CB.ENERGY&LT;&LT;ENDL;}

Run Results

3.write a function that takes a reference to a string object as a parameter and converts the contents of the string object to uppercase, using the function ToUpper () for this purpose: Then write a program that uses a loop that allows you to test the function with different inputs. The program runs as follows:

Enter a string (Q to quit): Go away
GO away
Next string (Q to quit): Good grief!
Good grief!
Next string (Q to quit): Q
Bye.

Code:

#include <iostream> #include <string>using namespace std;void wordupper (string &a); int main () {    String str;    cout << "Enter a string (1 to quit):";    Getline (CIN, str);    int i=0;    while (str! = "Q")    {        wordupper (str);        cout << str <<endl;        cout << "Next string (Q to quit):";        Getline (CIN, str);    }    cout << "bey!\n";    return 0;} void Wordupper (String &a) {    int i;    while (A[i])    {        A[i] = ToUpper (A[i]);        i++;}    }

Operation Result:

5.write the template function max5 (), which takes an array of 5 elements of type T as arguments.and returns the largest element in the array (because of the fixed length, so you can use the hardcode, without having to pass through parameters). Use this function in a program to replace T with theas an array containing 5 int values and an array containing 5 dowble values to test thefunction. Code:

#include <iostream>template<class t>t max5 (T ar[]) {    int n;    T max = ar[0];    for (n=1; n<5; n++)        if (Ar[n] > Max)            max = ar[n];    return Max;} const INT LIM = 5;int Main () {    using namespace std;    Double Ard[lim] = { -3.1, 8.1, -71.1, 34.4, 2.3};    int Ari[lim] = {2, 3, 9, 7};    Double MD;    int mi;    MD = MAX5 (ARD);    Mi = max5 (ARI);    cout << "Max double =" << MD <<endl;    cout << "Max int =" << mi <<endl;    return 0;}

Operation Result:

6.write the template function Maxn (), which will consist of an array of type T elements and a representation arrayAn integer of the number of elements as an argument and returns the largest element in the array. In the program to test ittest, the program uses an array of 6 int elements and a number containing 4 double elementsGroup to call the function. The program also contains a materialized array of char pointers and arrays ofThe number of pointers as parameters, and returns the address of the longest string. If you have more than one of these charactersstring, the address of the first one is returned. Use an array consisting of 5 string pointers totest the materialization. Code:

#include <iostream> #include <cstring>template<class t>t maxn (T ar[], int n) {int i;    T max = ar[0];    for (I=1; i<n; i++) if (Ar[i] > max) max = ar[i]; return Max;}    template<> const char * MAXN (const char * arr[], int n) {const char * max = arr[0];    int i;    for (I=1; i<n; i++) if (strlen (Arr[i]) > strlen (max)) max = Arr[i]; return Max;}    int main () {using namespace std;    int ari[6] = {8,4,2,7,10,22};    Double Ard[4] = {-3.1, 8.1,-71.1, 34.4}; const char * char_arr[5] = {"Hello world!", "What is your name?", "I Love You", "is Wonderf    UL "," HI "};    cout << "The max Integer of array is:" << maxn (Ari, 6) <<endl;    cout << "The max double of array is:" << MAXN (ARD, 4) <<endl;    cout << "The max string of array is:" << maxn (Char_arr, 5) <<endl; return 0;}

Operation Result:

7.Modify the program listing 8.14 so that the template function returns the sum of the array elements,Instead of displaying the contents of the array. The sum of the program thing and the sum of all debt.Code:

#include <iostream>template <typename t>t showarray (t arr[], int n), template <typename t>t Showarray (t   * arr[], int n); struct debts{char name[50]; double amount;};   int main (void) {using namespace std;   int things[6] = {13, 31, 103, 301, 310, 130};   struct debts Mr_e[3] = {{"Ima Wolfe", 2400.0}, {"Ura Foxe", 1300.0}, {"Iby Stout", 1800.0}};   double* Pd[3];   for (int i = 0; i < 3; i++) Pd[i] = &mr_E[i].amount;   cout<< "Listing Mr. E ' s counts of things:\n";   cout << Showarray (things,6) <<endl;   cout<< "Listing Mr E ' s debts:\n";   cout << Showarray (pd,3) <<endl; return 0;}   Template <typename t>t showarray (T arr[],int N) {using namespace std;   T total = 0;   cout<< "Template a\n";   for (int i = 0; i < n; i++) total +=arr[i]; return total;}   Template <typename t>t showarray (T * arr[], int n) {using namespace std;   T total = 0;   cout<< "Template b\n";for (int i = 0, i < n; i++) Total + = *arr[i]; return total;}

Operation Result:

C + + Primer eighth post-lesson programming questions