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32 lines
998 B
HTML
32 lines
998 B
HTML
<h1>字符函数 - isalpha</h1>
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<p>原型：extern int isalpha(int c);</p>
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<p>用法：#include <ctype.h></p>
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<p>功能：判断字符c是否为英文字母</p>
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<p>说明：当c为英文字母a-z或A-Z时，返回非零值，否则返回零</p>
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举例：
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<pre><code class="language-c">
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// isalpha.c
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#include <syslib.h>
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#include <ctype.h>
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#include <stdio.h>
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main()
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{
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int c;
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clrscr(); // clear screen
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printf("Press a key");
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for(;;)
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{
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c=getchar();
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clrscr();
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printf("%c: %s letter",c,isalpha(c)?"is":"not");
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}
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return 0; // just to avoid warnings by compiler
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}
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</code></pre>
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相关函数：<a href="isalnum.html">isalnum</a>,<a href="isdigit.html">isdigit</a>,<a href="isxdigit.html">isxdigit</a>,<a href="iscntrl.html">iscntrl</a>,<a href="isgraph.html">isgraph</a>,<a href="isprint.html">isprint</a>,<a href="ispunct.html">ispunct</a>,<a href=isspace.html">isspace</a>
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