Elem *e 是傳入地址值,e的值發(fā)生在函數(shù)體內(nèi)改變后會(huì)將原來(lái)的值同時(shí)改變,目的為了返回e的值

例:

void?swap(int?a,int?b){
????int?t=a;
????a=b;
????b=t;
}
void?swap2(int?*a,int?*b){
????int?t=*a;
????*a=*b;
????*b=t;
}
int?main(){
????int?a=2,b=3;
????swap(a,b);????//?a=2?b=3?(ab的值未發(fā)生改變)
????swap2(&a,&b);?//??a=3?b=2?(ab以完成交換)
}