84 lines
2.5 KiB
C++
84 lines
2.5 KiB
C++
|
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
|
||
|
|
* Champlain College SDEV-340-81
|
||
|
|
*
|
||
|
|
* C++ Week 5: Assignment (second semester) - Recursion Continued (2020/06/20)
|
||
|
|
*
|
||
|
|
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
|
||
|
|
*
|
||
|
|
* Working with recursion
|
||
|
|
* Recursion - Chapter 14 (Page 947)
|
||
|
|
* Programming Challenge (4. Recursive Array Sum) Sum numbers recursively
|
||
|
|
*
|
||
|
|
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
|
||
|
|
*
|
||
|
|
* Written by Llewellyn van der Merwe <llewellyn.vandermerw@mymail.champlain.edu>, June 2020
|
||
|
|
* Copyright (C) 2020. All Rights Reserved
|
||
|
|
* License GNU/GPL Version 2 or later - http://www.gnu.org/licenses/gpl-2.0.html
|
||
|
|
*
|
||
|
|
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
|
||
|
|
|
||
|
|
#include <iostream>
|
||
|
|
#include <vector>
|
||
|
|
#include <sstream>
|
||
|
|
|
||
|
|
using namespace std;
|
||
|
|
|
||
|
|
int sumRecursive(int n, int array[]);
|
||
|
|
|
||
|
|
int main() {
|
||
|
|
// string to get user input
|
||
|
|
string user_input;
|
||
|
|
// now ask for the integers
|
||
|
|
cout << "Enter space separated list of integers you would like to sum:" << endl;
|
||
|
|
// get the user input of integer
|
||
|
|
getline(cin, user_input);
|
||
|
|
// convert to string stream
|
||
|
|
stringstream user_input_stream(user_input);
|
||
|
|
// the vector array of integers
|
||
|
|
vector<int>array;
|
||
|
|
int number;
|
||
|
|
while(user_input_stream >> number){
|
||
|
|
// add the number
|
||
|
|
array.push_back(number);
|
||
|
|
// skip empty space
|
||
|
|
if(user_input_stream.peek() == ' ') user_input_stream.ignore();
|
||
|
|
}
|
||
|
|
// get size
|
||
|
|
int SIZE = array.size();
|
||
|
|
// start array of int
|
||
|
|
int arr[SIZE];
|
||
|
|
// little counter for +
|
||
|
|
number = 0;
|
||
|
|
// print out the numbers entered and build array
|
||
|
|
for(int val : array) {
|
||
|
|
// add to array
|
||
|
|
arr[number] = val;
|
||
|
|
// increment the number
|
||
|
|
number++;
|
||
|
|
// print out the value
|
||
|
|
cout << val;
|
||
|
|
// just add for the first numbers
|
||
|
|
if(number < SIZE) {
|
||
|
|
cout << " + ";
|
||
|
|
}
|
||
|
|
}
|
||
|
|
// give back answer
|
||
|
|
cout << " = " << sumRecursive(SIZE, arr) << endl;
|
||
|
|
}
|
||
|
|
|
||
|
|
// multiply numbers recursively
|
||
|
|
int sumRecursive(int n, int array[]) {
|
||
|
|
// lower to previous index
|
||
|
|
--n;
|
||
|
|
// get current value
|
||
|
|
int number = array[n];
|
||
|
|
// are we at the first element
|
||
|
|
if (n == 0) {
|
||
|
|
// return first "last" number
|
||
|
|
return number;
|
||
|
|
} else {
|
||
|
|
// recursive call
|
||
|
|
return number + sumRecursive(n , array);
|
||
|
|
}
|
||
|
|
}
|