1: //find_end2a.cpp
3: #include <iostream>
4: #include <vector>
5: #include <algorithm>
6: using namespace std;
8: /**
9: Tests if two positive integers have the same digit sum.
10: Pre:\n i1 and i2 have been initialized and i1, i2 are both > 0.
11: Post:\n Returns true if sum of the digits in i1 is == sum of digits
12: in i2, and otherwise returns false.
13: */
14: bool digitSumsAreSame
15: (
16: int i1, //in
17: int i2 //in
18: )
19: {
20: int digitSum1 = 0;
21: while (i1 != 0)
22: {
23: digitSum1 += i1 % 10;
24: i1 /= 10;
25: }
27: int digitSum2 = 0;
28: while (i2 != 0)
29: {
30: digitSum2 += i2 % 10;
31: i2 /= 10;
32: }
33: return digitSum1 == digitSum2;
34: }
36: int main()
37: {
38: cout << "\nThis program illustrates the use of the STL find_end() "
39: "algorithm (extended\nversion) to find the last occurrence of one "
40: "range of matching integer values\nin a vector within another "
41: "range of integer values, also in a vector, and\nwhere "
42: "corresponding values match if and only if they have the "
43: "same digit sum.";
44: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
46: int a1[] = {17, 21, 13, 5, 6, 7, 8, 12, 31, 14, 9, 10, 11};
47: vector<int> v1(a1, a1+13);
48: cout << "\nHere are the contents of v1:\n";
49: for (vector<int>::size_type i=0; i<v1.size(); i++)
50: cout << v1.at(i) << " ";
51: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
53: int a2[] = {21, 13, 5};
54: vector<int> v2(a2, a2+3);
55: cout << "\nHere are the contents of v2:\n";
56: for (vector<int>::size_type i=0; i<v2.size(); i++)
57: cout << v2.at(i) << " ";
58: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
60: vector<int>::iterator p;
62: p = find_end(v1.begin(), v1.end(), v2.begin(), v2.end(),
63: digitSumsAreSame);
64: if (p != v1.end())
65: cout << "\nThe last instance of v2 in v1 begins at location "
66: << (int)(p-v1.begin()+1) << ".";
67: else
68: cout << "\nNo instance of v2 was found in v1.";
69: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
70: }