 Data Streams  Numeric Output  Numeric Input  Multiple Numeric Output  Multiple Numeric Input  Character Output  Character Input  String Output  String Input  Current Position Pointer

Input and output is accomplished via streams in C++. A stream is a flow (movement) of data

int a; cin >> a; cout << a;

//file I/O int a; fin >> a; fout << a; //console I/O int a; cin >> a; cout << a;

#include using std::ofstream; int main() { ofstream fout; fout.open("junk.dat"); int a = 17; fout << a; fout.close(); return 0; }

#include using std::ofstream; int main() { ofstream fout; fout.open("junk.dat"); int a = 17; fout << a; fout.close(); return 0; }

#include using std::ofstream; int main() { ofstream fout; fout.open("junk.dat"); int a = 17; fout << a; fout.close(); return 0; }

1. Include the correct header files 2. Set up a stream object 3. Attach a file to the stream object 4. Write to file using the stream object 5. Close file

# include using std::ifstream; int main() { ifstream fin; fin.open("junk.dat"); int a; fin >> a; fin.close(); return 0; }

#include using std::ifstream; int main() { ifstream fin; fin.open("junk.dat"); int a; fin >> a; fin.close(); return 0; }

#include using std::ifstream; int main() { ifstream fin; fin.open("junk.dat"); int a; fin >> a; fin.close(); return 0; }

#include using std::ofstream; using std::endl; int main() { ofstream fout; fout.open("junk.dat"); int i; for (i = 10; i < 110; i += 10) fout << i << endl; fout.close(); return 0; }

fout << i << endl ; fout << i ;

#include using std::ifstream; #include using std::cout; int main() { ifstream fin; fin.open("junk.dat"); int a; while (fin >> a) cout << a << endl ; fin.close(); return 0; } junk.dat

#include using std::ifstream; #include using std::cout; int main() { ifstream fin; fin.open("junk.dat"); int a; while (fin >> a) cout << a << endl ; fin.close(); return 0; } junk.dat

#include #include using std::ofstream; #include using std::cin; int main() { char ch; ofstream fout; fout.open("test.dat"); while ( cin.get(ch) && (ch != '\n') ) fout.put(ch);

char buf[] = "Feed a child fish & he eats for one day. Teach him to fish and he eats forever."; int i; for (i = 0; i < (int)strlen(buf); ++i) fout.put(buf[i]); fout.close(); return 0; }

#include using std::ifstream; #include using std::cout; int main() { char ch; ifstream fin; fin.open("test.dat"); while(fin.get(ch)) cout << ch; fin.close(); return 0; }

#include using std::ofstream; using std::ios; #include using std::cin; using std::endl; #include

int main() { char buf[80]; ofstream fout; fout.open("test.dat"); while(cin.getline(buf, 80) &&(strlen(buf) > 0)) fout << buf << endl;

fout << "Better to remain quiet\n"; fout << "and be thought a fool\n"; fout << "that to open one's mouth\n"; fout << "and erase all doubts.\n"; fout.close(); return 0; }

#include using std::ifstream; #include using std::cout; using std::endl; int main() { char buf[80]; ifstream fin; fin.open("test.dat"); while(fin.getline(buf, 80)) cout << buf << endl; fin.close(); return 0; }

#include using std::ifstream; #include using std::cout; using std::endl; int main() { char buf[80]; ifstream fin; fin.open("test.dat"); while(fin.getline(buf, 80)) cout << buf << endl; fin.close(); return 0; }

fout << x; //write x to file fin >> x; //read data from file into x fout.put(ch); //write character in ch onto file fin.get (ch); //read 1 character from file into ch fout << “Kow\n"; //write a string onto file fin.getline(b, 80); //read a string into array b

ifstream fin; fin.open("junk.dat"); int a; while (fin >> a) cout << a << endl ; junk.dat CP

ifstream fin; fin.open("junk.dat"); int a; while (fin >> a) cout << a << endl ; junk.dat CP

ifstream fin; fin.open("junk.dat"); int a; while (fin >> a) cout << a << endl ; junk.dat CP

Data Stream Numeric Output Numeric Input Multiple Numeric Output Multiple Numeric Input Character Output Character Input String Output String Input Current Position Poi nter