c++常用函数摘抄

1 template <class ForwardIterator, class T>
2   void fill (ForwardIterator first, ForwardIterator last, const T& val)
3 {
4   while (first != last) {
5     *first = val;
6     ++first;
7   }
8 }

 1 // fill algorithm example
 2 #include <iostream>     // std::cout
 3 #include <algorithm>    // std::fill
 4 #include <vector>       // std::vector
 5 
 6 int main () {
 7   std::vector<int> myvector (8);                       // myvector: 0 0 0 0 0 0 0 0
 8 
 9   std::fill (myvector.begin(),myvector.begin()+4,5);   // myvector: 5 5 5 5 0 0 0 0
10   std::fill (myvector.begin()+3,myvector.end()-2,8);   // myvector: 5 5 5 8 8 8 0 0
11 
12   std::cout << "myvector contains:";
13   for (std::vector<int>::iterator it=myvector.begin(); it!=myvector.end(); ++it)
14     std::cout << ‘ ‘ << *it;
15   std::cout << ‘\n‘;
16 
17   return 0;
18 }

myvector contains: 5 5 5 8 8 8 0 0

1 template <class T> void swap ( T& a, T& b )
2 {
3   T c(a); a=b; b=c;
4 }

 1 // swap algorithm example (C++11)
 2 #include <iostream>     // std::cout
 3 #include <utility>      // std::swap
 4 
 5 int main () {
 6 
 7   int x=10, y=20;                  // x:10 y:20
 8   std::swap(x,y);                  // x:20 y:10
 9 
10   int foo[4];                      // foo: ?  ?  ?  ?
11   int bar[] = {10,20,30,40};       // foo: ?  ?  ?  ?    bar: 10 20 30 40
12   std::swap(foo,bar);              // foo: 10 20 30 40   bar: ?  ?  ?  ?
13 
14   std::cout << "foo contains:";
15   for (int i: foo) std::cout << ‘ ‘ << i;
16   std::cout << ‘\n‘;
17 
18   return 0;
19 }

foo contains: 10 20 30 40