binary search and qsort in c++ (bsearch, qsort)

bsearchqsort.cpp

#include <iostream>
#include <string.h>

using namespace std;

int compare(const void *a, const void *b){
  return (*(int *)a- *(int*)b);
}

int str_compare(const void *a, const void *b) {
  return strcmp((char*)a, (char*)b);
}

void sorter() {
  int a[]= {1,-2,-13,4,5,6,7};
  qsort(a, 7, sizeof(int), compare);
  for(int c: a){
    cout<<c<<" ";
  }
}

void searcher() {
  int *key;
  int p= 11;
  int a[]= {1,2,3,4,5,6,7};
  key= (int*)bsearch(&p, a, 7, sizeof(int), compare); //returns void*
  if (key== NULL)
    cout<<p<<" not found";
  else
    cout<<*key<<" found";
  cout<<endl;
}

void searcher_string() {
  char *key;
  char p[]= "hello";
  char a[][6]= {"hell", "hola", "hello", "bello" };
  qsort(a, 4, 6, str_compare);
  
  cout<<a[0]<<endl;
  
  key= (char*) bsearch(p, a, 4, 6, str_compare); //returns void*
  if (key== NULL)
    cout<<p<<" not found";
  else
    cout<<key<<" found";
  cout<<endl;
}

int main() {
  //searcher();
  searcher_string();
  //sorter();
  return 0;
}