update exercises chapter 2 to 6

Author: Heatwave

README.md

@@ -32,11 +32,73 @@ Source code and solutions of exercises to _The C Programming Language 2nd Editio
 1. 1-24 skipped
 
 ### 2. Types operators expressions
+1. [2-1](./chapter-2-types-operators-expressions/1.ranges-of-variables.c)
+1. [2-2](./chapter-2-types-operators-expressions/2.loop-without-logical-operators.c)
+1. [2-3](./chapter-2-types-operators-expressions/3.atoi.c)
+1. [2-4](./chapter-2-types-operators-expressions/8.squeeze2.c)
+1. [2-5](./chapter-2-types-operators-expressions/9.any.c)
+1. [2-6](./chapter-2-types-operators-expressions/11.setbits.c)
+1. [2-7](./chapter-2-types-operators-expressions/12.invert.c)
+1. [2-8](./chapter-2-types-operators-expressions/13.rightrot.c)
+1. [2-9](./chapter-2-types-operators-expressions/15.bitcount2.c)
+1. [2-10](./chapter-2-types-operators-expressions/16.lower2.c)
 
 ### 3. Control flow
+1. [3-1](./chapter-3-control-flow/01.binsearch.c)
+1. 3-2
+      * [escape](./chapter-3-control-flow/03.escape.c)
+      * [unescape](./chapter-3-control-flow/04.unescape.c)
+1. [3-3](./chapter-3-control-flow/08.expand.c)
+1. [3-4](./chapter-3-control-flow/09.itoa.c)
+1. [3-5](./chapter-3-control-flow/10.itob.c)
+1. [3-6](./chapter-3-control-flow/11.itoa.c)
 
 ### 4. Functions and program structure
+1. [4-1](./chapter-4-functions-and-program-structure/2.strrindex.c)
+1. [4-2](./chapter-4-functions-and-program-structure/3.atof-test.c)
+1. [4-3, 4-3, 4-5, 4-6](./chapter-4-functions-and-program-structure/4.reverse-polish-calculator.c)
+1. [4-7](./chapter-4-functions-and-program-structure/getch.c)
+1. [4-8](./chapter-4-functions-and-program-structure/getch.c)
+1. 4-9 skipped
+1. 4-10 skipped
+1. [4-11](./chapter-4-functions-and-program-structure/5.getop-with-static.c)
+1. [4-12](./chapter-4-functions-and-program-structure/9.itoa-recursive.c)
+1. [4-13](./chapter-4-functions-and-program-structure/10.reverse.recursive.c)
+1. [4-14](./chapter-4-functions-and-program-structure/11.swap-macro.c)
 
 ### 5. pointers and arrays
+1. [5-1](./chapter-5-pointers-and-arrays/3.getint.c)
+1. [5-2](./chapter-5-pointers-and-arrays/4.getfloat.c)
+1. [5-3](./chapter-5-pointers-and-arrays/15.strcat-pointer.c)
+1. [5-4](./chapter-5-pointers-and-arrays/16.strend.c)
+1. 5-5
+      * [strcpy](17.strncpy.c)
+      * [strncat](18.strncat.c)
+      * [strncmp](19.strncmp.c)
+1. [5-6](./chapter-5-pointers-and-arrays/20.getline-pointer.c)
+1. [5-7](./chapter-5-pointers-and-arrays/24.pointer-arrays-without-alloc.c)
+1. [5-8](./chapter-5-pointers-and-arrays/27.year-month-day-pointer.c)
+1. [5-9](./chapter-5-pointers-and-arrays/27.year-month-day-pointer.c)
+1. [5-10](./chapter-5-pointers-and-arrays/32.expr.c)
+1. 5-11
+      * [detab](./chapter-5-pointers-and-arrays/33.detab.c)
+      * [entab](./chapter-5-pointers-and-arrays/34.entab.c)
+1. 5-12
+      * [detab](./chapter-5-pointers-and-arrays/35.detab-arg.c)
+      * [entab](./chapter-5-pointers-and-arrays/36.entab-arg.c)
+1. [5-13](./chapter-5-pointers-and-arrays/37.tail.c)
+1. [5-14](./chapter-5-pointers-and-arrays/39.sort-with-r.c)
+1. [5-15](./chapter-5-pointers-and-arrays/40.sort-with-f.c)
+1. [5-16](./chapter-5-pointers-and-arrays/41.sort-with-d.c)
+1. 5-17 skipped
+1. [5-18](./chapter-5-pointers-and-arrays/43.dcl-error-handle.c)
+1. [5-19](./chapter-5-pointers-and-arrays/44.undcl.c)
+1. 5-20 skipped
 
 ### 6. structures
+1. [6-1](./chapter-6-structures/3.getword.c)
+1. [6-2](./chapter-6-structures/6.variables-group.c)
+1. [6-3](./chapter-6-structures/7.words-appear-lines.c)
+1. 6-4 skipped
+1. [6-5](./chapter-6-structures/)
+1. [6-6](./chapter-6-structures/)