1: //merge2a.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 merge() "
39: "algorithm (extended\nversion) to merge two ordered ranges of "
40: "integer values from two different\nvectors of integers into a "
41: "single ordered range of values within another\nvector of "
42: "integers. The order of values is determined by one value "
43: "preceding \nanother if and only if the first has a smaller "
44: "digit sum than the second.";
45: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
47: int a1[] = {11, 41 , 45, 59, 98};
48: vector<int> v1(a1, a1+5);
49: cout << "\nHere are the contents of v1:\n";
50: for (vector<int>::size_type i=0; i<v1.size(); i++)
51: cout << v1.at(i) << " ";
52: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
54: int a2[] = {121, 13, 6, 52, 44, 36, 28, 69};
55: vector<int> v2(a2, a2+8);
57: cout << "\nHere are the contents of v2:\n";
58: for (vector<int>::size_type i=0; i<v2.size(); i++)
59: cout << v2.at(i) << " ";
60: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
62: vector<int> v3(15);
63: cout << "\nHere are the contents of v3:\n";
64: for (vector<int>::size_type i=0; i<v3.size(); i++)
65: cout << v3.at(i) << " ";
66: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
68: cout << "\nNow merge the contents of v1 and v2 into v3.";
69: merge(v1.begin(), v1.end(), v2.begin(), v2.end(), v3.begin(),
70: hasSmallerDigitSum);
71: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
73: cout << "\nHere are the revised contents of v3:\n";
74: for (vector<int>::size_type i=0; i<v3.size(); i++)
75: cout << v3.at(i) << " ";
76: cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
77: }