Why my program is not working

#include
using namespace std;

int binarySearch(int a[],int n,int key){
int s=0;
int e=n-1;
int mid;

while(s<=0){
mid=(s+e)/2;

if(a[mid]==key){
    return mid;
}

else if(a[mid]>key){
    e=mid-1;
}
else
{
    s=mid+1;  
}

}
return -1;

}

int main(){
int n,key;
cin>>n;
int a[1005];

for (int i = 0; i < n; i++)
{
    cin>>a[i];
}  
cin>>key;
int res=binarySearch(a,n,key);

if (res==-1)
{
cout<<“not present”;
}
else
{
cout<<res;
}

return 0;

}

@souravrao3110
hello sourav,
please save ur code at https://ide.codingblocks.com/ and share thr generated link here