2014c语言（分章节练习）

p;\rif ((pgetenv("MOUSE")) ! =NULL) /*0@ getenv()\rÛÜÏÐÝÞ€*/\r(\rif(!strcmp(p, YES))\rprintf (''Mouse is OK )[\r)\relse\rprintf ( No mouse");\rgetch();\r}\r7. 3. 3 àáâãäå\rttinclude stdio. h\r^include stdlib. h \rttinclude ctype. h\r^include conio. h \rmain ()\r{\rvoid checksys(char);\rchar ch;\rdo (.\rprintf ( ZA: display directory 6):\rprintf ( ZB: display disk info 6):\rprintf (6C: change system date 6):\rprintf(6Q: quit Input your choice:");\rch=toupper (getchar());\rchecksys (ch);\r} while (ch!='Q');\rgetchar ();\r)\rvoid checksys(char c)\r(\rswitch(c)\rcase 'A' : system( ZDIR C:\*. )\rbreak;\rcase ' B' : system(6CHKDSK6): break;\rcase ' C' : system(6TIME6): break;