小编use*_*150的帖子

我正在尝试学习c ++并尝试使用sort和qsort.sort()工作正常,但qsort没有,我不知道为什么,所以你可以帮助我,这是我试图编译的代码

#include<iostream>
#include<vector>
#include<cstdlib>
#include<ctime>
#include<algorithm>


using namespace std;

int compvar(const void *one, const void *two)
{
    int a = *((int*)one);
    int b = *((int*)two);
    if (a<b)
       return -1;
    if (a == b)
       return 0;
    return 1;   

}

void bvect(vector<int> &vec, int num)
{
     srand(time(NULL));
     for(int i=0; i<num; ++i)
             vec.push_back(rand()%1000 + 1);
}

void showvec(vector<int> vec)
{
     for (int i=0; i<vec.size(); ++i)
         cout<<vec[i]<<endl;
}


int main()
{
    vector<int>numbers;
    bvect(numbers, 1000);
    showvec(numbers);
    qsort(numbers.begin(), numbers.size(), sizeof(int), compvar);
    showvec(numbers);

    return 0;
}

我正在尝试编译一个简单的libpcap示例,

#include<stdio.h>
#include<pcap.h>

int main(int argc, char *argv[])
{
  char *dev;
  char errbuf[PCAP_ERRBUF_SIZE];
  struct bpf_program fp;

  char filter_exp[] = "port 23";
  bpf_u_int32 mask;
  bpf_u_int32 net;
  dev = pcap_lookupdev(errbuf);
  if (dev == NULL )
  {
    fprintf(stderr, "couldn't find default device: %s\n", errbuf);
    return (2);
  }
  printf("Device: %s\n", dev);

  //LOOKUP NETMASK and IP
  if (pcap_lookupnet(dev, &net, &mask, errbuf) == -1)
  {
    fprintf(stderr, "can't get netmask for device %s\n", dev);
    net = 0;
    mask = 0;
  }

  printf("lookup\n");

  pcap_t *handle;
  printf("handle defined\n");
  handle …