第6题：
当number<length，显示数组时数组未被赋值的地方会出现乱码，可以通过初始化数组a[]来改善。
#include <iostream>
using namespace std;
int Fill_array(double a[],int length);
void Show_array(double a[], int length);
void Reverse_array(double a[], int length);
int main()
{
double a[10];
int length = 10;
int number;
number=Fill_array(a, length);
cout << number << endl;
Show_array(a, length);
Reverse_array( a, length);
Show_array(a, length);
Reverse_array(a+1, length-2);
Show_array(a, length);
return 0;
}
int Fill_array(double a[], int length)
{
double in;
int i;
i = 0;
while (cin>>in && i<length )
{
a[i] = in;
i++;
}
return i;
}
void Show_array(double a[], int length)
{
for (int i=0;i<length;i++)
{
cout<< a[i]<<"\t";
}
cout << endl;
}
void Reverse_array(double a[], int length)
{
for (int i = 0; i < length/2; i++)
{
int temp;
temp = a[i];
a[i] = a[length-1- i];
a[length - 1 - i] = temp;
}
}
第7题：
#include <iostream>
const int Max = 5;
double* fill_array(double ar[], int limit);
void show_array(const double ar[], double* tail);
void revalue(double r, double ar[], double* tail);
int main()
{
using namespace std;
double properties[Max];
double* tail = fill_array(properties, Max);
show_array(properties, tail);
if (tail)
{
cout << "Enter revaluation factor:";
double factor;
while (!(cin >> factor))
{
cin.clear();
while (cin.get() != '\n')
continue;
cout << "Bad input;Please enter a number:";
}
revalue(factor, properties, tail);
show_array(properties, tail);
}
cout << "Done.\n";
cin.get();
cin.get();
return 0;
}
double* fill_array(double ar[], int limit)
{
using namespace std;
double temp;
int i;
for (i = 0; i < limit; i++)
{
cout << "Enter value #" << (i + 1) << ":";
cin >> temp;
if (!cin)
{
cin.clear();
while (cin.get() != '\n')
continue;
cout << "Bad input;input process terminated.\n";
break;
}
else if (temp < 0)
break;
ar[i] = temp;
}
return &ar[i];
}
void show_array(const double ar[], double* tail)
{
using namespace std;
for (int i = 0; &ar[i] < tail; i++)
{
cout << "Property #" << (i + 1) << ": $";
cout << ar[i] << endl;
}
}
void revalue(double r, double ar[], double* tail)
{
for (int i = 0; &ar[i] < tail; i++)
ar[i] *= r;
}
第8题：
a:
#include <iostream>
#include <string>
const int Seasons = 4;
using namespace std;
const char*Snames[4] = { "Spring","Summer","Fall","Winter" };
void fill(double pa[]);
void show(double da[]);
int main()
{
double expenses[4];
fill(expenses);
show(expenses);
return 0;
}
void fill(double pa[])
{
for (int i=0;i<Seasons;i++)
{
cout << "Enter " << Snames[i] << " expenses: ";
cin >> pa[i];
}
}
void show(double da[])
{
double total = 0.0;
cout << "\nEXPENSES\n";
for (int i=0;i<Seasons;i++)
{
cout << Snames[i] << ": $" << da[i] << endl;
total += da[i];
}
cout << "Total Expenses:$" << total << endl;
}
b:
#include <iostream>
#include <string>
const int Seasons = 4;
using namespace std;
const char*Snames[4] = { "Spring","Summer","Fall","Winter" };
struct number
{
double data[4];
};
void fill(number *pa);
void show(number da);
int main()
{
number expenses;
fill(&expenses);
show(expenses);
return 0;
}
void fill(number* pa)
{
for (int i=0;i<Seasons;i++)
{
cout << "Enter " << Snames[0] << " expenses: ";
cin >> (*pa).data[i];
}
}
void show(number da)
{
double total = 0.0;
cout << "\nEXPENSES\n";
for (int i=0;i<Seasons;i++)
{
cout << Snames[i] << ": $" << da.data[i] << endl;
total += da.data[i];
}
cout << "Total Expenses:$" << total << endl;
}
第9题：
#include <iostream>
#include <string>
#pragma warning(disable:4996)
using namespace std;
const int SLEN = 30;
struct student
{
char fullname[SLEN];
char hobby[SLEN];
int ooplevel;
};
int getinfo(student pa[], int n);
void display1(student st);
void display2(const student* ps);
void display3(const student pa[], int n);
int main()
{
cout << "Enter class size:";
int class_size;
cin >> class_size;
while (cin.get() != '\n')
{
continue;
}
student* ptr_stu = new student[class_size];
int entered = getinfo(ptr_stu, class_size);
for (int i = 0; i < entered; i++)
{
display1(ptr_stu[i]);
display2(&ptr_stu[i]);
}
display3(ptr_stu, entered);
delete[] ptr_stu;
cout << "Done\n";
return 0;
}
int getinfo(student pa[], int n)
{
int number;
number = 0;
string name;
string fa;
for (number; number < n; number++)
{
getline(cin, name);
getline(cin, fa);
if (strcmp(&name[0], " ") == 0)
{
break;
}
if (name.length()>SLEN)
{
name[SLEN - 1] = '\0';
}
if (fa.length()>SLEN)
{
fa[SLEN - 1] = '\0';
}
strcpy(pa[number].fullname, &name[0]);
strcpy(pa[number].hobby, &fa[0]);
}
return number;
}
void display1(student st)
{
if (st.fullname)
{
cout << st.fullname << ":"<< st.hobby << endl;
}
}
void display2(const student* ps)
{
if (ps->fullname)
{
cout << ps->fullname << ":"<< ps->hobby << endl;
}
}
void display3(const student pa[], int n)
{
int i;
for (i = 0; i < n; i++)
{
cout << pa[i].fullname << ":" << pa[i].hobby << endl;
}
}
第10题：
函数指针：
#include <iostream>
#include <string>
#pragma warning(disable:4996)
using namespace std;
double add(double x, double y);
double min(double x, double y);
double calculate(double x, double y, double (*pf)(double x, double y));
int main()
{
while (1)
{
double x, y;
cout << "请输入x和y：";
cin >> x >> y;
cout << "两个数字的和为："<<calculate(x, y,add)<<endl;
cout << "两个数字的差为："<<calculate(x, y, min)<<endl;
}
return 0;
}
double add(double x, double y)
{
return x + y;
}
double min(double x, double y)
{
return x - y;
}
double calculate(double x, double y, double (*pf)(double x, double y))
{
return (*pf)(x, y);
}
指针数组：
#include <iostream>
#include <string>
#pragma warning(disable:4996)
using namespace std;
double add(double x, double y);
double min(double x, double y);
void calculate(double x, double y, double (*pf[ ])(double x, double y));
int main()
{
double (*pf[2])(double x, double y) = {add,min};
while (1)
{
double x, y;
cout << "请输入x和y：";
cin >> x >> y;
calculate(x, y, pf);
}
return 0;
}
double add(double x, double y)
{
return x + y;
}
double min(double x, double y)
{
return x - y;
}
void calculate(double x, double y, double (*pf[])(double x, double y))
{
for(int i=0;i<2;i++)
{
if (i==0)
{
cout << "两个数的和为：";
}
else
{
cout << "两个数的差为：";
}
cout<<(*pf[i])(x, y);
cout << endl;
}
}
|