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: