Question: I want to write an function to print an array from mth element to nth element where m<=n and if a is an array then function calling should looks like print(a+m,a+n). Noow what should be the user defined function for this case?
#include <stdio.h>
#include <iostream>
using namespace std;
/* It may be ok or not. If not then what program should write? */
void print(int a[], int n)
{
for(int i=0;; ++i){
if(a[i] == a[n]) break;
printf("%d ",a[i]);
}
}
int main()
{
int a[6] = {1,3,5,6,8,2};
/*We can use to sort this array of 1st n elements*/
sort(a,a+n);
/*if we want to use c function to sort this array 'a' for 1st 4 elements then we write*/
sort(a,a+4);
/*But if we want use to print 1st n elements than what should user defined function looks like?*/
print(a,a+3); //for this function to print 1st 3 elements what should write user defined function
return 0;
}
You can use pointers for such format
void print (int * begin, int * end){
while(begin != end){
printf("%d", *begin);
begin++;
}
}
Using the std::for_each algorithm would eliminate the use of pointers and eliminate the raw loop.
It could look something like:
#include <algorithm>
#include <array>
#include <iostream>
template<std::size_t T>
void PrintArray(const std::array<int,T> arrayToPrint, const int begin, const int end)
{
if(begin < end)
{
auto print = [&](const int& n){ std::cout << n << "\n";};
std::for_each(arrayToPrint.begin() + begin, arrayToPrint.begin() + end, print);
}
}
void CallFunction()
{
std::array<int, 6> numberArray = {1, 3, 5, 6, 8, 2};
PrintArray(numberArray, 0, 6);
}
(https://godbolt.org/z/FXGrCT)
You could use iterators, specifically std::ostream_iterator, in C++ to output to the output stream:
#include <algorithm>
#include <iterator>
#include <iostream>
template <typename T>
void print(T* start, T* end)
{
std::copy(start, end, std::ostream_iterator<T>(std::cout, " "));
}
//Call like this:
print(a, a+5);
where std::copy copies from the array, starting at start and ending at end, to the output stream. The second parameter to the std::ostream_iterator constructor is an optional delimiter string, written to the output stream after every write operation (here a space character).
