1: //equal_range2a.cpp
3: #include <iostream>
4: #include <vector>
5: #include <algorithm>
6: using namespace std;
8: /**
9: Tests if one integer has a smaller digit sum than another.
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 hasSmallerDigitSum
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 equal_range() "
39: "algorithm (extended\nversion) to find the lower bound and upper "
40: "bound locations of a given target\nvalue in a vector of integers "
41: "ordered in the sense that one integer precedes\nanother if the "
42: "digit sum in the first is less than the digit sum in the second.";
43: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
45: int a[] = {21, 13, 31, 40, 5, 51, 25, 52, 70,
46: 8, 62, 71, 45, 54, 55, 82, 38, 56,
47: 65, 92, 39, 48, 75, 49, 59, 88};
48: vector<int> v(a, a+26);
49: cout << "\nHere are the contents of v:\n";
50: for (vector<int>::size_type i=0; i<v.size(); i++)
51: cout << v.at(i) << " ";
52: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
54: pair<vector<int>::iterator, vector<int>::iterator> bounds;
56: bounds = equal_range(v.begin(), v.end(), 85, hasSmallerDigitSum);
57: if (bounds.first != v.end())
58: cout << "\nLower bound of 85 in v = " << *bounds.first;
59: if (bounds.first != v.end())
60: cout << "\nUpper bound of 85 in v = " << *bounds.second;
61: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
63: bounds = equal_range(v.begin(), v.end(), 96, hasSmallerDigitSum);
64: if (bounds.first != v.end())
65: cout << "\nLower bound of 96 in v = " << *bounds.first;
66: if (bounds.first != v.end())
67: cout << "\nUpper bound of 96 in v = " << *bounds.second;
68: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
70: bounds = equal_range(v.begin(), v.end(), 73, hasSmallerDigitSum);
71: if (bounds.first != v.end())
72: cout << "\nLower bound of 73 in v = " << *bounds.first;
73: if (bounds.first != v.end())
74: cout << "\nUpper bound of 73 in v = " << *bounds.second;
75: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
77: bounds = equal_range(v.begin(), v.end(), 1, hasSmallerDigitSum);
78: if (bounds.first != v.end())
79: cout << "\nLower bound of 1 in v = " << *bounds.first;
80: if (bounds.first != v.end())
81: cout << "\nUpper bound of 1 in v = " << *bounds.second;
82: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
84: bounds = equal_range(v.begin(), v.end(), 99, hasSmallerDigitSum);
85: if (bounds.first != v.end())
86: cout << "\nLower bound of 99 in v = " << *bounds.first;
87: if (bounds.first != v.end())
88: cout << "\nUpper bound of 99 in v = " << *bounds.second;
89: cout << "\nNote that both the lower and upper bound locations "
90: "\nof 99 are the end (one-past-the-last) vector position.";
91: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
92: }