uTools-Manuals/docs/c/isdigit.html

<h1>字符函数 - isdigit</h1>


  <p>原型：extern int isdigit(int c);</p>
  
  <p>用法：#include &lt;ctype.h></p>
  
  <p>功能：判断字符c是否为数字</p>
  
  <p>说明：当c为数字0-9时，返回非零值，否则返回零。</p>
  
  举例：<pre>

      // isdigit.c
      
      #include &lt;syslib.h>
      #include &lt;ctype.h>

      main()
      {
        int c;
        
        clrscr();        // clear screen
        c='a';
        printf("%c:%s\n",c,isdigit(c)?"yes":"no");
        c='9';
        printf("%c:%s\n",c,isdigit(c)?"yes":"no");
        c='*';
        printf("%c:%s\n",c,isdigit(c)?"yes":"no");
        getchar();
        return 0;
      }
      
  </pre>相关函数：<a href="isalnum.html">isalnum</a>,<a href="isalpha.html">isalpha</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>