Zilog Z80380 Manual de usuario descargar pdf (Pagina 70)

Library Functions Run Time Environment

4–6 UM004001-COR1103

atof, atoi, atol FUNCTIONS

Header file statement: #include <stdlib.h>

Syntax: double atof (const char *string);

int atoi( const char *string );

long atol( const char *string );

These functions convert a character string to a double-precision floating-point value (atof),

an integer value (atoi), or a long integer value (atol). The input string is a sequence of charac

ters that can be interpreted as a numerical value of the specified type.

The function stops reading the input string at the first character that it cannot recognize as

part of a number. This character may be the null character (‘\0’) terminating the string.

The atof function expects string to have the following form:

[whitespace] [sign] [digits] [.digits] [ {d | D | e | E }[sign]digits]

A whitespace consists of space and/or tab characters, which are ignored; sign is either plus

(+) or minus (-); and digits are one or more decimal digits. If no digits appear before the dec

imal point, at least one must appear after the decimal point. The decimal digits may be fol-

lowed by an exponent, which consists of an introductory letter ( d, D, e, or E) and an

optionally signed decimal integer.

The atoi and atol functions do not recognize decimal points or exponents. The string argu-

ment for these functions has the form

[whitespace] [sign]digits

where whitespace, sign, and digits are exactly as described above for atof.

Return Value

Each function returns the double, int, or long value produced by interpreting the input char-

acters as a number. The return value is 0 (for atoi), 0L (for atol), and 0.0 (for atof) if the input

cannot be converted to a value of that type.

• The return value is undefined in case of overflow.

Parameter Description

string String to be converted

1 2 ... 65 66 67 68 69 70 71 72 73 74 75 ... 115 116

Sin comentarios

Zilog Z80380 Manual de usuario Pagina 70