PracticeDev/study_cpp/cpp_primer_source_code/Chapter 8/twoswap.cpp

70 lines
1.5 KiB
C++

// twoswap.cpp -- specialization overrides a template
#include <iostream>
template <typename T>
void Swap(T &a, T &b);
struct job
{
char name[40];
double salary;
int floor;
};
// explicit specialization
template <> void Swap<job>(job &j1, job &j2);
void Show(job &j);
int main()
{
using namespace std;
cout.precision(2);
cout.setf(ios::fixed, ios::floatfield);
int i = 10, j = 20;
cout << "i, j = " << i << ", " << j << ".\n";
cout << "Using compiler-generated int swapper:\n";
Swap(i,j); // generates void Swap(int &, int &)
cout << "Now i, j = " << i << ", " << j << ".\n";
job sue = {"Susan Yaffee", 73000.60, 7};
job sidney = {"Sidney Taffee", 78060.72, 9};
cout << "Before job swapping:\n";
Show(sue);
Show(sidney);
Swap(sue, sidney); // uses void Swap(job &, job &)
cout << "After job swapping:\n";
Show(sue);
Show(sidney);
// cin.get();
return 0;
}
template <typename T>
void Swap(T &a, T &b) // general version
{
T temp;
temp = a;
a = b;
b = temp;
}
// swaps just the salary and floor fields of a job structure
template <> void Swap<job>(job &j1, job &j2) // specialization
{
double t1;
int t2;
t1 = j1.salary;
j1.salary = j2.salary;
j2.salary = t1;
t2 = j1.floor;
j1.floor = j2.floor;
j2.floor = t2;
}
void Show(job &j)
{
using namespace std;
cout << j.name << ": $" << j.salary
<< " on floor " << j.floor << endl;
}