代码B: #include <time.h> #include <stdio.h> class NoSuchElementException {}; class IllegalStateException {}; class List { class Element { public: const int datum; Element* next; inline Element(const int datum, Element* next) :datum(datum),next(next) {} }; class Iter { Element* curr; public: inline Iter(Element* head) :curr(head) {} inline bool hasNext()const { return curr != 0; } inline int next() { if(curr == 0) throw NoSuchElementException(); const int result = curr->datum; curr = curr->next; return result; } }; Element* head; Element* tail; public: inline List() { head = tail = 0; } inline bool isEmpty() { return head == 0; } void purge() { Element* curr = head; Element* next; while(curr!=0) { next = curr->next; delete curr; curr = next; } head = tail = 0; } inline void append(const int datum) { if(head == 0) { head = tail = new Element(datum,0); } else { tail->next = new Element(datum, 0); tail = tail->next; } } void extract(const int datum) { if(isEmpty()) throw NoSuchElementException(); Element* curr = head; Element* pre = 0; while(curr != 0 && curr->datum != datum) { pre = curr; curr = curr->next; } if(curr == 0) throw NoSuchElementException(); if(curr == head) { Element* next = head->next; delete head; head = next; } else { pre->next = curr->next; delete curr; } if(curr == tail) tail = pre; } void assign(List* another) { if(this == another) return; Iter* iter = another->iterator(); purge(); while(iter->hasNext()) { append(iter->next()); } delete iter; } inline Iter* iterator() { return new Iter(head); } }; int main() { List from,to; const int length = 100000; const int innerLoops = 100; for(int i=0;i<length;i++) from.append(i); clock_t start,end; double timeuse; for(int i=0;i<3;i++) { printf("loop %d:\n",i); timeuse = 0; for(int k=0;k<innerLoops;k++) { to.purge(); start = clock(); for(int j=0;j<length;j++) to.append(j); end = clock(); timeuse+=(double)(end-start); } printf("append: %3.1f M/s\t",length/timeuse*innerLoops/1000); timeuse = 0; for(int k=0;k<innerLoops;k++) { to.purge(); start = clock(); to.assign(&from); end = clock(); timeuse+=(double)(end-start); } printf("assign: %3.3f/s\t",innerLoops/timeuse*1000); start = clock(); for(int j=length/2;j<(length/2+1000);j++) to.extract(j); end = clock(); timeuse=(double)(end-start); printf("extract: %3.3fk/s\t",1000/timeuse); timeuse = 0; for(int k=0;k<innerLoops;k++) { to.assign(&from); start = clock(); to.purge(); end = clock(); timeuse+=(double)(end-start); } printf("purge: %3.3f/s\n",innerLoops/timeuse*1000); } } 编译方式: cl /G7 /O2 /arch:SSE2 list.cpp 注:我是p4,所以/G7 /arch:SSE2不是的把它去掉就是了

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