Range Based For Loops: It is the new form of for loop, it iterates ALL elements of given range, array or stl collection(like vector).
Its syntax: for(ele : coll){ statement;} //ele is deceleration of each element and coll is collection
//Array
int arr[]{1,2,3,4,5,6,7,8,9};
//Use reference with const, if want to read only
for(const auto & ele: arr)
{
std::cout<<ele<<" ";
}
std::cout<<std::endl;
//Use reference if want to modify
for(auto & ele: arr)
{
std::cout<<ele*2<<" ";
}
std::cout<<std::endl;
Complete source code with example:
#include<iostream>
#include<vector>
int main()
{
std::cout<<"Range Based for Loops"<<std::endl;
//Array
int arr[]{1,2,3,4,5,6,7,8,9};
//Use reference with const, if want to read only
for(const auto & ele: arr)
{
std::cout<<ele<<" ";
}
std::cout<<std::endl;
//Use reference if want to modify
for(auto & ele: arr)
{
std::cout<<ele*2<<" ";
}
std::cout<<std::endl;
//Vector
std::vector<int> v{1,2,3,4,5};
//Use reference with const, if want to read only
for(const auto & ele: v)
{
std::cout<<ele<<" ";
}
std::cout<<std::endl;
//If want to use begin() and end(),they are provided by stl only
for(auto pos=v.begin(); pos!=v.end();++pos)
{
auto& ele = *pos;
std::cout<<ele<<" ";
}
std::cout<<std::endl;
return 0;
}
Output:
Range Based for Loops 1 2 3 4 5 6 7 8 9 2 4 6 8 10 12 14 16 18 1 2 3 4 5 1 2 3 4 5