tailieunhanh - Beej's Guide to C Programming

And they lived happily ever after. The End. What's this? You say something's still not clear about this whole C programming language thing? Well, to be quite honest, I'm not even sure what the above code does. It's a snippet from one of the entires in the 2001 International Obfuscated C Code Contest 1, a wonderful competition wherein the entrants attempt to write the most unreadable C code possible, with often surprising results. The bad news is that if you're a beginner in this whole thing, all C code you see looks obfuscated! The good news is, it's not going to. | Beej s Guide to C Programming Brian Beej Hall beej@ Revision alpha-25 May 17 2007 Copyright 2007 Brian Beej Hall Contents 1. . Audience 1 . Platform and Compiler 1 . Building under Unix 2 . Official Homepage 2 . Email Policy 2 . Mirroring 2 . Note for Translators 3 . Copyright and Distribution 3 2. Programming Building . The Specification 4 . The Implementation 5 . So Much To Do So Little Time 6 . Hello World 7 3. Variables Expressions and Statements Oh My .10 . Variables 10 . Operators 11 . Expressions 12 . Statements 12 4. Building Blocks 5. . Passing by Value 20 . Function Prototypes 20 6. Variables The . Up Scope 22 . Storage Classes 24 7. Pointers--Cower In Fear .26 . Memory and Variables 26 . Pointer Types 27 . Dereferencing 28 . Passing Pointers as Parameters 28 8. . Pointers to structs 31 . Passing struct pointers to functions 32 9. . Passing arrays to functions 35 ii Contents 10. 11. Dynamic . malloc 40 . free 41 . realloc 41 . calloc 43 12. More Stuff .44 . Pointer Arithmetic 44 . typedef 45 . enum 46 . More struct declarations 47 . Command Line Arguments 48 . Multidimensional Arrays 50 . Casting and promotion 51 . Incomplete types 52 . void pointers 53 . NULL pointers 54 . More Static 55 . Typical Multifile Projects 56 . The Almighty C Preprocessor 58 . Pointers to pointers 61 . Pointers to Functions 63 . Variable Argument Lists 65 13. Standard I O . fopen 71 . freopen 73 . fclose 75 . printf fprintf 76 . scanf fscanf 81 . gets fgets 84 . getc fgetc getchar 86 . puts fputs 88 . putc fputc putchar 89 . fseek rewind 90 . ftell 92 . fgetpos fsetpos 93 . ungetc 94 . fread 96 . fwrite 98 . feof ferror .