»ªÎªC/C++±ÊÊÔÌâ(¸½´ð°¸)

http://www.teecool.com/post/2007081104.html
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int a = 4;
(A)a += (a++); (B) a += (++a) ;(C) (a++) += a;(D) (++a) += (a++);
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1.д³öÅжÏABCDËĸö±í´ïʽµÄÊÇ·ñÕýÈ·, ÈôÕýÈ·, д³ö¾­¹ý±í´ïʽÖÐ aµÄÖµ(3·Ö)
int a = 4;
(A)a += (a++); (B) a += (++a) ;(C) (a++) += a;(D) (++a) += (a++);
a = ?
´ð£ºC´íÎó£¬×ó²à²»ÊÇÒ»¸öÓÐЧ±äÁ¿£¬²»Äܸ³Öµ£¬¿É¸ÄΪ(++a) += a;
¸Äºó´ð°¸ÒÀ´ÎΪ9,10,10,11
2.ij32λϵͳÏÂ, C++³ÌÐò£¬Çë¼ÆËãsizeof µÄÖµ(5·Ö).
char str[] = “http://www.ibegroup.com/”
char *p = str ;
int n = 10;
Çë¼ÆËã
sizeof (str ) = £¿£¨1£©
sizeof ( p ) = £¿£¨2£©
sizeof ( n ) = £¿£¨3£©
void Foo ( char str[100]){
Çë¼ÆËã
sizeof( str ) = £¿£¨4£©
}
void *p = malloc( 100 );
Çë¼ÆËã
sizeof ( p ) = £¿£¨5£©
´ð£º£¨1£©17 £¨2£©4 £¨3£© 4 £¨4£©4 £¨5£©4
3. »Ø´ðÏÂÃæµÄÎÊÌâ. (4·Ö)
(1).Í·ÎļþÖÐµÄ ifndef/define/endif ¸ÉʲôÓã¿Ô¤´¦Àí
´ð£º·ÀֹͷÎļþ±»Öظ´ÒýÓÃ
(2). ££i nclude ºÍ ££i nclude “filename.h” ÓÐʲôÇø±ð£¿
´ð£ºÇ°ÕßÓÃÀ´°üº¬¿ª·¢»·¾³ÌṩµÄ¿âÍ·Îļþ£¬ºóÕßÓÃÀ´°üº¬×Ô¼º±àдµÄÍ·Îļþ¡£
(3).ÔÚC++ ³ÌÐòÖе÷Óñ» C ±àÒëÆ÷±àÒëºóµÄº¯Êý£¬ÎªÊ²Ã´Òª¼Ó extern “C”ÉùÃ÷£¿
´ð£ºº¯ÊýºÍ±äÁ¿±»C++±àÒëºóÔÚ·ûºÅ¿âÖеÄÃû×ÖÓëCÓïÑԵIJ»Í¬£¬±»extern "C"ÐÞÊεıä
Á¿ºÍº¯ÊýÊÇ°´ÕÕCÓïÑÔ·½Ê½±àÒëºÍÁ¬½ÓµÄ¡£ÓÉÓÚ±àÒëºóµÄÃû×Ö²»Í¬£¬C++³ÌÐò²»ÄÜÖ±½Óµ÷
ÓÃC º¯Êý¡£C++ÌṩÁËÒ»¸öC Á¬½Ó½»»»Ö¸¶¨·ûºÅextern“C”À´½â¾öÕâ¸öÎÊÌâ¡£
(4). switch()Öв»ÔÊÐíµÄÊý¾ÝÀàÐÍÊÇ?
´ð£ºÊµÐÍ
4. »Ø´ðÏÂÃæµÄÎÊÌâ(6·Ö)
(1).Void GetMemory(char **p, int num){
*p = (char *)malloc(num);
}
void Test(void){
char *str = NULL;
GetMemory(&str, 100);
strcpy(str, "hello");
printf(str);
}
ÇëÎÊÔËÐÐTest º¯Êý»áÓÐʲôÑùµÄ½á¹û£¿
´ð£ºÊä³ö“hello”
(2). void Test(void){
char *str = (char *) malloc(100);
strcpy(str, “hello”);
free(str);
if(str != NULL){
strcpy(str, “worl