C++ STL algorithm, mismatch() program example
Compiler: Visual C++ Express Edition 2005
Compiled on Platform: Windows XP Pro SP2
Header file: Standard
Additional project setting: Set project to be compiled as C++
Project -> your_project_name Properties -> Configuration Properties -> C/C++ -> Advanced -> Compiled As: Compiled as C++ Code (/TP)
Other info: none
To do: Using the C++ mismatch() to compare two ranges element by element either for equality or equivalent in a sense specified by a binary predicate and locates the first position where a difference occurs in C++ programming
To show: How to use the C++ algorithm, mismatch() to compare two ranges element by element either for equality or equivalent in a sense specified by a binary predicate and locates the first position where a difference occurs in C++ programming
// C++ STL algorithm, mismatch()
#include <vector>
#include <list>
#include <algorithm>
#include <iostream>
using namespace std;
// return whether second element is twice the first
bool twice(int elem1, int elem2)
{ return ((elem1 * 2) == elem2);}
int main(void)
{
// containers
vector <int> vec1, vec2;
list <int> lst;
// iterators
vector <int>::iterator Iter1, Iter2;
list <int>::iterator lst_Iter, lst_inIter;
int i, j, k;
// pushing data in ranges
for(i = 0; i <= 5; i++)
vec1.push_back(5*i);
for(j = 0; j <= 7; j++)
lst.push_back(5*j);
for(k = 0; k <= 5; k++)
vec2.push_back(10*k);
// print the data
cout<<"vec1 vector data: ";
for(Iter1 = vec1.begin(); Iter1 != vec1.end(); Iter1++)
cout<<*Iter1<<" ";
cout<<endl;
cout<<"lst list data: ";
for(lst_Iter = lst.begin(); lst_Iter!= lst.end(); lst_Iter++)
cout<<*lst_Iter<<" ";
cout<<endl;
cout<<"vec2 vector data: ";
for(Iter2 = vec2.begin(); Iter2 != vec2.end(); Iter2++)
cout<<*Iter2<<" ";
cout<<endl;
// testing vec1 vector and lst list for mismatch under identity
pair<vector <int>::iterator, list <int>::iterator> result1;
result1 = mismatch(vec1.begin(), vec1.end(), lst.begin());
cout<<"\nOperation: mismatch(vec1.begin(), vec1.end(), lst.begin())"<<endl;
if(result1.first == vec1.end())
cout<<"The two ranges do not differ."<<endl;
else
cout<<"The fist mismatch is between "<<*result1.first<<" and "<<*result1.second<<endl;
// modifying the lst list
cout<<"\nDo some operation on the lst list..."<<endl;
lst_inIter = lst.begin();
lst_inIter++;
lst_inIter++;
lst.insert(lst_inIter, 70);
// print the data
cout<<"The modified lst list data: ";
for(lst_Iter = lst.begin(); lst_Iter!= lst.end(); lst_Iter++)
cout<<*lst_Iter<<" ";
cout<<endl;
// testing vec1 vector with modified lst list for mismatch under identity
cout<<"\nOperation: mismatch(vec1.begin(), vec1.end(), lst.begin())"<<endl;
result1 = mismatch(vec1.begin(), vec1.end(), lst.begin());
if(result1.first == vec1.end())
cout<<"The two ranges do not differ"<<endl;
else
cout<<"The first mismatch is between "<<*result1.first<<" and "<<*result1.second<< endl;
// test vec1 and vec2 vectors for mismatch under the binary predicate twice
pair<vector <int>::iterator, vector <int>::iterator> result2;
cout<<"\nOperation: mismatch(vec1.begin(), vec1.end(), vec2.begin(), twice)"<<endl;
result2 = mismatch(vec1.begin(), vec1.end(), vec2.begin(), twice);
if(result2.first == vec1.end())
cout<<"The two ranges do not differ based on the binary predicate twice()"<<endl;
else
cout<<"The first mismatch is between "<<*result2.first<<" and "<<*result2.second<<endl;
return 0;
}
Output examples:
vec1 vector data: 0 5 10 15 20 25
lst list data: 0 5 10 15 20 25 30 35
vec2 vector data: 0 10 20 30 40 50
Operation: mismatch(vec1.begin(), vec1.end(), lst.begin())
The two ranges do not differ.
Do some operation on the lst list...
The modified lst list data: 0 5 70 10 15 20 25 30 35
Operation: mismatch(vec1.begin(), vec1.end(), lst.begin())
The first mismatch is between 10 and 70
Operation: mismatch(vec1.begin(), vec1.end(), vec2.begin(), twice)
The two ranges do not differ based on the binary predicate twice()
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