strcpy,strlen的源代码

char * strcpy( char *strDest, const char *strSrc )

{

assert( (strDest != NULL) && (strSrc != NULL) );

char *address = strDest;

while( (*strDest++ = * strSrc++) != ‘/0’ );

return address;

}

int strlen( const char *str ) //输入参数const
{ assert( strt != NULL ); //断言字符串地址非0

int len;

while( (*str++) != '/0' )

{ len++; }

return len;

}

浮点型变量并不精确，所以不可将float变量用“==”或“！=”与数字比较，应该设法转化成“>=”或“<=”形式。如果写成if (x == 0.0)，则判为错