sort+函数指针、sort+比较器对象、qsort速度比较

#include<bits/stdc++.h>
using namespace std;
#define MAXN 50000000
struct TS {
    int a, b, c;
};
inline bool cmp(const TS& t1, const TS& t2) {
    if(t1.a != t2.a)return t1.a < t2.a;
    if(t1.b != t1.b)return t1.b < t2.b;
    return t1.c <= t2.c;
}

int cmp4qsort(const void* a, const void* b) {
    TS *t1 = (TS*)a, *t2 = (TS*)b;
    if(t1->a != t2->a)return t1->a - t2->a;
    if(t1->b != t2->b)return t1->b - t2->b;
    return t1->c - t2->c;
}

struct cmpFunctor {
    inline bool operator() (const TS& t1, const TS& t2) {
        if(t1.a != t2.a)return t1.a < t2.a;
        if(t1.b != t1.b)return t1.b < t2.b;
        return t1.c <= t2.c;
    }
};
TS tss[MAXN];

void gen(){
    ;i < MAXN;++i){
        tss[i].a = rand() * rand();
        tss[i].b = rand() * rand();
        tss[i].c = rand() * rand();
    }
}

int main() {
    srand((unsigned)time(NULL));
    gen();
    clock_t st = clock();
    sort(tss, tss + MAXN, cmp);
    printf("sort by function pointer:%ld\n", clock() - st);

    gen();
    st = clock();
    sort(tss, tss + MAXN, cmpFunctor());
    printf("sort by functor:%ld\n", clock() - st);

    gen();
    st = clock();
    qsort(tss, MAXN, ]), cmp4qsort);
    printf("qsort by function pointer:%ld\n", clock() - st);
    ;
}