5.5 memccpy（拷贝内存内容）............................................................................................40
5.6 memchr（在某一内存范围中查找一特定字符）..........................................................41
5.7 memcmp（比较内存内容）.............................................................................................41
5.8 memcpy（拷贝内存内容）..............................................................................................42
5.9 memmove（拷贝内存内容）...........................................................................................43
5.10 memset（将一段内存空间填入某值）.........................................................................43
5.11 rindex（查找字符串中最后一个出现的指定字符）...................................................44
5.12 strcasecmp（忽略大小写比较字符串）........................................................................45
5.13 strcat（连接两字符串）.................................................................................................45
5.14 strchr（查找字符串中第一个出现的指定字符）........................................................46
5.15 strcmp（比较字符串）...................................................................................................47
5.16 strcoll（采用目前区域的字符排列次序来比较字符串）...........................................47
5.17 strcpy（拷贝字符串）....................................................................................................48
5.18 strcspn（返回字符串中连续不含指定字符串内容的字符数）..................................49
5.19 strdup（复制字符串）....................................................................................................49
5.20 strlen（返回字符串长度）.............................................................................................50
5.21 strncasecmp（忽略大小写比较字符串）......................................................................51
5.22 strncat（连接两字符串）...............................................................................................51
5.23 strncpy（拷贝字符串）..................................................................................................52
5.24 strpbrk（查找字符串中第一个出现的指定字符）......................................................52
5.25 strrchr（查找字符串中最后出现的指定字符）...........................................................53
5.26 strspn（返回字符串中连续不含指定字符串内容的字符数）....................................54
5.27 strstr（在一字符串中查找指定的字符串）.................................................................54
5.28 strtok（分割字符串）.....................................................................................................55
6 math function.................................................................................................................................56
6.1 abs（计算整型数的绝对值）..........................................................................................56
6.2 acos（取反余弦函数数值）............................................................................................56
6.3 asin（取反正弦函数值）.................................................................................................57
6.4 atan（取反正切函数值）.................................................................................................58
6.5 atan2（取得反正切函数值）...........................................................................................58
6.6 ceil（取不小于参数的最小整型数）..............................................................................59
6.7 cos（取余玄函数值）......................................................................................................59
6.8 cosh（取双曲线余玄函数值）........................................................................................60
6.9 exp（计算指数）..............................................................................................................61
6.10 frexp（将浮点型数分为底数与指数）.........................................................................61
6.11 ldexp（计算 2 的次方值）.............................................................................................62
6.12 log（计算以 e 为底的对数值）.....................................................................................62
6.13 log10（计算以 10 为底的对数值）...............................................................................63
6.14 pow（计算次方值）.......................................................................................................64
6.15 sin（取正玄函数值）.....................................................................................................64
6.16 sinh（取双曲线正玄函数值）.......................................................................................65
6.17 sqrt（计算平方根值）....................................................................................................65
6.18 tan（取正切函数值）.....................................................................................................66
6.19 tanh（取双曲线正切函数值）.......................................................................................67
