C标准库函数实现
fopen
freopen
fflush
fclose
remove
rename
tmpfile
tmpnam
setvbuf
setbuf
printf
fprintf
sprintf
vprintf
vfprintf
vsprintf
scanf
fscanf
sscanf
getc
putc
gets
puts
getchar
putchar
fgets
fputs
fgetc
fputc
ungetc
fread
fwrite
fseek
fteel
rewind
fgetpos
fsetpos
clearerr
feof
ferror
perror
isalnum
isalpha
isblank
iscntrl
isdigit
islower
isascii
isgraph
isprint
ispunct
isspace
isupper
isxdigit
toascii
tolower
toupper
strcpy
strncpy
strcat
strncat
strcmp
strncmp
strchr
strrchr
strspn
strcspn
strpbrk
strlen
strerror
strstr
strtok
memcpy
memcmp
memmove
memset
memchr
sin
asin
cos
acos
tan
atan
atan2
sinh
cosh
tanh
exp
log
log10
pow
sqrt
ceil
floor
ldexp
frexp
modf
fmod
atof
atoi
atol
strtod
strtol
strtoul
rand
srand
calloc
malloc
realloc
free
abort
exit
atexit
systen
getenv
bsearch
qsort
abs
labs
div
ldiv
assert
va_start
va_end
va_arg
setjmp
longjmp
signal
raise
clock
time
difftime
localtime
mktime
asctime
ctime
gmtime
strftime