This paper relates to copying and replacement algorithm, arithmetic generation algorithm, the set of algorithms used
Need to traverse, search, sorting algorithms can read my previous article
1, and copy replacement algorithm
（1）copy
Element within the container specified range are copied to another vessel
Function prototype
copy（iterator beg，iterator end，iterator dest）；beg begin iterator
end end iterator
dest target starting iterator
Examples
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>
void print(int val)
{
cout<<val<<" ";
}
void test01()
{
vector<int>v1;
for(int i=0;i<10;i++)
{
v1.push_back(i);
}
vector<int>v2;
v2.resize(v1.size());
copy(v1.begin(),v1.end(),v2.begin());
for_each(v2.begin(),v2.end(),print);
cout<<endl;
}
int main()
{
test01();
}（2）replace
The container specified in the scope of the old elements to modify new element
Function prototype
replace（iterator beg，iterator end，oldvalue，newvalue）；The old elements within the interval replaced with a new element
beg begin iterator
end end iterator
oldvalue old elements
newwalue new element
Examples
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>
class MyPrint
{
public:
bool operator()(int val)
{
cout<<val<<" ";
}
};
void test01()
{
vector<int>v1;
v1.push_back(1);
v1.push_back(5);
v1.push_back(3);
v1.push_back(5);
v1.push_back(5);
cout<<"替换前："<<endl;
for_each(v1.begin(),v1.end(),MyPrint());
cout<<endl;
replace(v1.begin(),v1.end(),5,521);
cout<<"替换后："<<endl;
for_each(v1.begin(),v1.end(),MyPrint());
}
int main()
{
test01();
}All the old elements are replaced with new elements
（3）replace_if
The elements within the interval satisfying the condition, replace the specified element
Function prototype
replace_if（iterator beg，iterator end，_pred，newvalue）；Alternatively conditional replacement element, to meet the conditions specified element
beg begin iterator
end end iterator
pred predicate
newvalue replaced with new elements
Examples
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>
class MyPrint
{
public:
bool operator()(int val)
{
cout<<val<<" ";
}
};
class Greater
{
public:
bool operator()(int val)
{
return val>3;
}
};
void test01()
{
vector<int>v1;
v1.push_back(1);
v1.push_back(5);
v1.push_back(3);
v1.push_back(5);
v1.push_back(5);
cout<<"替换前："<<endl;
for_each(v1.begin(),v1.end(),MyPrint());
cout<<endl;
replace_if(v1.begin(),v1.end(),Greater(),1000);
cout<<"替换后："<<endl;
for_each(v1.begin(),v1.end(),MyPrint());
}
int main()
{
test01();
}（4）swap
Two interchangeable container element
Function prototype
swap（container c1，container c2）；Two interchangeable container element
c1 container 1, c2 container 2
2, the arithmetic generation algorithm
Arithmetic algorithm generation algorithm is small, the header file is included when using
#include <numeric>（1）accumulate
The cumulative sum calculating section container element
Function prototype
accumulate（iterator beg，iterator end，value）；Calculating the cumulative sum container element
beg begin iterator
end end iterator
the accumulated value of the starting value
Examples
#include<iostream>
using namespace std;
#include<vector>
#include<numeric>
class Greater
{
public:
bool operator()(int val)
{
return val>3;
}
};
void test01()
{
vector<int>v;
for(int i=0;i<100;i++)
{
v.push_back(i+1);
}
int num=accumulate(v.begin(),v.end(),0);
cout<<"num="<<num<<endl;
}
int main()
{
test01();
}（2）fill
The vessel filled with the specified element
Function prototype
fill（iterator beg， iterator end， value）；beg begin iterator
end end iterator
Value of filling value
Examples
#include<iostream>
using namespace std;
#include<vector>
#include<numeric>
#include<algorithm>
class MyPrint
{
public:
bool operator()(int val)
{
cout<<val<<" ";
}
};
void test01()
{
vector<int>v;
v.resize(10);
for_each(v.begin(),v.end(),MyPrint());
fill(v.begin(),v.end(),100);
cout<<endl;
for_each(v.begin(),v.end(),MyPrint());
}
int main()
{
test01();
}3, a collection of commonly used algorithm
（1）set_intersection
The intersection of two sets of
Function prototype
set_intersection(iterator beg1，iterator end1，iterator beg2，iterator end2，iterator dest）；Two sets must be ordered sequence
beg1 container 1 starts iterator
end1 container 1 ends iterator
beginning the container 2 beg2 iterator
end2 container 2 ends iterator
dest target vessel began iterator
Examples
#include<iostream>
using namespace std;
#include<vector>
#include<numeric>
#include<algorithm>
class MyPrint
{
public:
bool operator()(int val)
{
cout<<val<<" ";
}
};
void test01()
{
vector<int>v1;
vector<int>v2;
for(int i=0;i<10;i++)
{
v1.push_back(i);
v2.push_back(i+5);
}
vector<int>v3;
v3.resize(min(v1.size(),v2.size()));
vector<int>::iterator it=set_intersection(v1.begin(),v1.end(),v2.begin(),v2.end(),v3.begin());
for_each(v3.begin(),it,MyPrint());
}
int main()
{
test01();
}set_intersection function returns an iterator, with an iterator accepts, as the end target iterator
（2）set_union
Sum of two sets of set and
Function prototype
set_union（iterator beg1，iterator end1，iterator beg2，iterator end2，iterator dest）；Two sets must be ordered sequence
1 start beg1 container iterator
end1 end iterator container 1
beg2 container 2 starts iterators
end2 container 2 end iterator
dest target container starts iterator
#include<iostream>
using namespace std;
#include<vector>
#include<numeric>
#include<algorithm>
class MyPrint
{
public:
bool operator()(int val)
{
cout<<val<<" ";
}
};
void test01()
{
vector<int>v1;
vector<int>v2;
for(int i=0;i<10;i++)
{
v1.push_back(i);
v2.push_back(i+5);
}
vector<int>v3;
v3.resize(v1.size()+v2.size());
vector<int>::iterator it=set_union(v1.begin(),v1.end(),v2.begin(),v2.end(),v3.begin());
for_each(v3.begin(),it,MyPrint());
}
int main()
{
test01();
}（3）set_difference
Differencing the two sets set
Function prototype
set_difference（iterator beg1，iterator end1，iterator beg2，iterator end2，iterator dest）；Two sets must be ordered sequence
beg1容器1开始迭代器
end1 容器1结束迭代器
beg2容器2开始迭代器
end2容器2结束迭代器
dest 目标容器开始迭代器
不过这里有一个前后顺序需要注意
差集：
v1: 0,1,2,3,4,5,6,7,8,9
v2: 5,6,7,8,9,10,11,12,13,14
v1对v2的差集为：0，1，2，3，4，
v2对v1的差集为:10,11,12,13,14
实例
#include<iostream>
using namespace std;
#include<vector>
#include<numeric>
#include<algorithm>
class MyPrint
{
public:
bool operator()(int val)
{
cout<<val<<" ";
}
};
void test01()
{
vector<int>v1;
vector<int>v2;
for(int i=0;i<10;i++)
{
v1.push_back(i);
v2.push_back(i+5);
}
vector<int>v3;
v3.resize(max(v1.size(),v2.size()));
vector<int>::iterator it=set_difference(v1.begin(),v1.end(),v2.begin(),v2.end(),v3.begin());
cout<<"v1对v2的差集为："<<endl;
for_each(v3.begin(),it,MyPrint());
vector<int>v4;
v4.resize(max(v1.size(),v2.size()));
vector<int>::iterator it2=set_difference(v2.begin(),v2.end(),v1.begin(),v1.end(),v4.begin());
cout<<endl<<"v2对v1的差集为："<<endl;
for_each(v4.begin(),it2,MyPrint());
}
int main()
{
test01();
}