c51头函数(国外英语资料).doc

c51头函数(国外英语资料) Character processing function This category function is used to handle individual characters, including character class testing and character case conversion Header file ctype.h Function list Function classes, functions, uses, details Character tests for letters and numbers isalnum Does the letter isalpha? Do you want to control the character iscntrl? Is the number isDigit? Is it possible to display characters (except for space extra) isgraph Is it possible to display characters (including spaces) isprint Whether it is a blank, not letter and numeric display character ispunct Is the space isspace? Do you have capital letters isupper? Whether 16 hexadecimal numbers (0-9, A-F) character isxdigit The character case conversion function is converted to uppercase toupper Convert to lowercase letter tolower Regionalization Functions of this class are used to handle language differences in different countries. Header file local.h Function list Function classes, functions, uses, details Area control area set up setlocale Digital format convention query country currency, date, time format conversion localeconv Mathematical function This classification gives various mathematical calculations, and it must be reminded that the data format in the C ANSI standard does not conform to the IEEE754 standard, and some C language compilers follow IEEE754 (for example, frinklin, C51) Header file math.h Function list Function classes, functions, uses, details Error condition processing defines domain errors (the input parameter value of the function is not within the specified range) Range error (the return value of the function is not within the specified range) Trigonometric inverse cosine ACOs Inverse sine asin Arc tangent atan Cut 2 atan2 anyway Cosine cos Sinusoidal sin Tangent Tan Hyperbolic function, hyperbolic cosine, cosh Hyperbolic sine Sinh Hyperbolic tangent tanh Exponential and logarithmic exponential functions, exp Exponential decomposition function frexp P