1: //TestStuff22.cpp
2: //Thursday, Mar 06, 2014
3:
4: #include <iostream>
5: #include <string>
6: #include <iomanip>
7: #include <cstdlib>
8: using namespace std;
9:
10: int main(int argc, char* argv[])
11: {
12: //string s = "Hello, world!";
13: //cout << s << endl;
14: //
15: //Can use length() or size() for number of characters in s
16: //cout << s.length() << endl;
17:
18: //Can use [] or at() to get a single character
19: //cout << s[1] << endl;
20: //cout << s.at(1) << endl;
21:
22: //C++ string objects are not immutable
23: //s.at(1) = 'E';
24: //cout << s << endl;
25:
26: //Two versions of substr()
27: //cout << s.substr(7) << endl;
28: //cout << s.substr(7, 5) << endl;
29:
30: //Here a is just an array of characters, *not* a C-string
31: //int a[] = {1, 2, 3};
32: //for (int i = 0; i < 3; i++)
33: //{
34: // cout << a[i] << " ";
35: //}
36: //cout << endl;
37:
38: //Here s1 is also just an array of characters
39: //char s1[] = {'H', 'e', 'l', 'l', 'o'};
40: //for (int i = 0; i < 5; i++)
41: //{
42: // cout << s1[i];
43: //}
44: //cout << endl;
45: //cout << s1 << endl;
46:
47: //But here s2 *is* a C-string, and so has a '\0' (null character)
48: //at the end, which allows all the legacy C-string functions in
49: //<cstring> to work properly with it
50: //char s2[] = "Hello";
51: //for (int i = 0; i < 5; i++)
52: //{
53: // cout << s2[i];
54: //}
55: //cout << endl;
56:
57: //Can do this with a C-string, but not with an array of characters
58: //cout << s2 << endl;
59:
60: //Outputs all command-line parameters, one per line
61: //for (int i = 0; i < argc; i++)
62: //{
63: // cout << argv[i] << endl;
64: //}
65:
66: //atoi() converts a C-string to an integer.
67: //It comes from <cstdlib>.
68: cout << atoi(argv[1]) + atoi(argv[2]) << endl;
69: }
70: