File

1. File • File – Unit of logical storage • Aid in manipulating exact sector of file data • Abstract view of secondary physical storage devices • Without files • You can’t process codes or other text-related material • You can’t run programs • You can’t run operating systems • Meaning, computers have only hardware

2. File • Files are very important! • From running a command to idle time, files are being used • Other programs need to access other files too • Like the basic algorithms on sorting (last week’s lab)

3. File add #include <stdio.h> int main(intargc, char** argv){ FILE *file; file = fopen("haha.txt","w"); if(file == NULL){ fprintf(stderr,"File can't be opened!"); exit(1);} fprintf(file,"Hello World"); fclose(file); return 0; }

4. Constructor Declaration • Declaring variables already allocates memory (like inti;) • The same goes for declaring files (FILE *fp;) • A default zero variable for the constructor is created automatically the moment it is declared • Object is being instantiated at the moment of declaration (only applies in C++) • ONLY IN C++ can you create constructors for your files • C does not allow this (because declaration != assignment)

5. HelloWorld.cpp (C++ version) #include <iostream> #include <fstream> using namespace std; int main( void ){ ofstreamfout; fout.open( "HelloWorld.txt" ); if( fout.is_open() ) { fout << "Hello World!\n"; fout.close(); } return 0; }

6. HelloWorld.cpp (C++ version) #include <iostream> #include <fstream> using namespace std; int main( void ){ ofstreamfout(“HelloWorld.txt”); //explicit constructor call if( fout.is_open() ) { fout << "Hello World!\n"; fout.close(); } return 0; }

7. Reading of Files #include <stdio.h> char line[128]; int main(intargc, char** argv){ FILE *file; file = fopen(argv[1],"r"); if(file == NULL){ fprintf(stderr,"File can't be opened!"); exit(1);} while(fgets(line,sizeof(line),file) != NULL){ printf(line); } fclose(file); return 0;}

8. Lab 3: Binary Converter • Create a file binaryconvert.c that converts a text file into an 8-bit binary file and vice versa (following the ASCII convention) • Use C (not C++) to process binary files • In short, don’t use the binary libraries in converting a number to binary • Make sure that the output is printed out in a .bin file. And the content of that is just 1’s and 0’s. • I should be able to run this program, provided that my other argument is a .txt file that will serve as the text to be converted

9. Lab 3: Binary Converter • I should be able to do the reverse, meaning that if the file is a .bin file, then it converts it to a .txt file that converts the binaries to a text • This should still be divided into 8 bits (following the format for ASCII characters) • I can run this using the command: ./binaryconvert input.txt(for text to binary) ./binaryconvertinput.bin (for binary to text)

10. Lab 3: Binary Converter • Of course, I should be able to see your Certificate of Authorship. Failure to do this will null and void your lab!!! • Deadline: Tomorrow, 11:55 pm • Submit it with the following format: CS162B_Lab3_<Section>_<Surname>_<ID Number>.tar

11. Next Week… • More C/C++ • Pointers • Multiple Inheritance • Assembly • Take Home Lab 1

12. The End Dreams are a big picture of what you want. PLANS are the specifics of that dream.