📄 string.conversion.html
字号:
<html><!-- #BeginTemplate "/Templates/tmpl.dwt" --><!-- DW6 --><head><!-- #BeginEditable "doctitle" --> <title>PTypes: string: conversion</title><!-- #EndEditable --> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link rel="stylesheet" href="styles.css"></head><body bgcolor="#FFFFFF" leftmargin="40" marginwidth="40"><p><a href="../index.html"><img src="title-20.png" width="253" height="39" alt="C++ Portable Types Library (PTypes) Version 2.0" border="0"></a> <hr size="1" noshade><!-- #BeginEditable "body" --> <p class="hpath"><a href="index.html">Top</a>: <a href="basic.html">Basic types</a>: <a href="string.html">string</a>: Conversion</p><blockquote> <pre class="lang">#include <ptypes.h>string itostring(<i><ordinal</i>> value);string itostring(<i><ordinal</i>> value, int base, int width = 0, char pad = ' ');large stringtoi(const string& s);large stringtoie(const string& s);ularge stringtoue(const string& s, int base);string lowercase(const string& s);</pre></blockquote><p><br>PTypes provides 3 different string-to-int conversion functions: <span class="lang">stringtoi()</span>, <span class="lang">stringtoie()</span> and <span class="lang">stringtoue()</span>. The first function <span class="lang">stringtoi()</span> is for non-negative decimal numbers; it returns -1 on error. The other two functions with a suffix 'e' in their names ('e' is for 'exception') may throw exceptions, but they accept the full range of 64-bit values.</p><p>These functions replace the CRTL functions <span class="lang">atoll()</span> and <span class="lang">strtoll()</span> which are not implemented on all systems.</p><p>Both function families, string-to-int and int-to-string, accept numeration bases in the range 2 to 64. The 64-digit numeration uses all digits, letters and also '.' and '/'. It may be useful for representing, for example, MD5 checksums in a compact printable form (see function <span class="lang">outmd5::get_digest()</span> in src/pmd5.cxx).<br></p><p><span class="def">string itostring(<i><ordinal></i> value)</span> converts the given ordinal <span class="lang">value</span> to a string. Various overloaded versions of this function accept ordinal values of different sizes and signness.</p><p><span class="def">string itostring(<i><ordinal</i>> value, int base, int width = 0, char pad = ' ')</span> converts an integer value to a string with the numeration base specified by <span class="lang">base</span>, which can be in the range 2 - 64. To right-justify the resulting string you can specify <span class="lang">width</span> and <span class="lang">pad</span> parameters. If the numeration base is greater than 36 in addition to digits and letters <span class="lang">itostring()</span> uses '.' and '/' characters and also lowercase letters. For numeration bases other than 10 the parameter <span class="lang">value</span> is always treated as unsigned.</p><p><span class="def">large stringtoi(const string& s)</span> converts a string to a 64-bit integer. This function accepts only <b>positive decimal large numbers</b> and 0. It returns -1 if the string does not represent a valid positive number or an overflow occurred.</p><p><span class="def">large stringtoie(const string& s)</span> converts a string to a 64-bit integer. This function accepts <b>signed decimal large numbers</b>. Unlike <span class="lang">stringtoi()</span>, this function may throw an exception of type <span class="lang">(econv*)</span> if the string does not represent a valid number or an overflow occurred.</p><p><span class="def">unsigned large stringtoue(const string& s, int base)</span> converts a string to an unsigned 64-bit integer using the numeration base specified by <span class="lang">base</span>. This function accepts <b>unsigned large numbers</b>. It may throw an exception of type <span class="lang">(econv*)</span> if the string does not represent a valid number or an overflow occurred. <span class="lang">Base</span> can be in the range 2 - 64. For numeration bases from 2 to 36 this function uses digits and letters, and the letter case is insignificant. For numeration bases grater than 36, '.', '/' and lowercase letters are used additionaly.</p><p><span class="def">string lowercase(const string& s)</span> converts all characters of the given string <span class="lang">s</span> to lower case. The current version of the library "understands" only lower ASCII characters; all other characters remain unchanged. This function can effectively detect if all characters in the string are already in lower-case to avoid unnecessary string allocations. </p><p class="seealso">See also: <a href="string.constructors.html">Constructors/destructors</a>, <a href="string.operators.html">Operators</a>, <a href="string.typecasts.html">Typecasts</a>, <a href="string.manipulation.html">Manipulation</a> </p><!-- #EndEditable --><hr size="1"><a href="../index.html" class="ns">PTypes home</a></body><!-- #EndTemplate --></html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -