segmentation fault in recursive binary searching [closed] - c++

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I want to binary search more than once using the same function but it's showing segmentation fault. For one input its giving correct answer but when I am giving multiple input for binary search(i.e, q>1 acc. to my code) then its showing segmentation fault.
#include <iostream>
#include <bits/stdc++.h>
using namespace std;
int binarySearch(int x[],int l, int r, long int m ){
if(r>=1){
int mid=(r-1)/2+l;
if (x[mid]==m) return mid;
if (x[mid]>m) return binarySearch(x,l,mid-1,m);
if (x[mid]<m) return binarySearch(x,mid+1,r,m);
}
return 0;
}
int main(){
int n,q;
cin>>n;
int x[n];
for(int i=0;i<n;i++){cin>>x[i];}
int t = sizeof(x) / sizeof(x[0]);
sort(x,x+t);
cin>>q;
while (q--){
long int m;
cin>>m;
cout<<binarySearch(x,0,t-1,m)<<endl;
}
return 0;
}

Answer 1

The condtion r>=1 should be r-l+1>=1 to check if there are some element in the range.
The initialization int mid=(r-1)/2+l; should be int mid=(r-l)/2+l; to correctly calculate the middle element.
Variable-Length Array int x[n]; is not in the standard C++. You should use heap allication int *x = new int[n]; instead. After that, n should be used for the initialization of t because the technique to obtain the number of elements in arrays won't work with pointers.
#include <iostream>
#include <algorithm>
using namespace std;
int binarySearch(int x[],int l, int r, long int m ){
if(r-l+1>=1){
int mid=(r-l)/2+l;
if (x[mid]==m) return mid;
if (x[mid]>m) return binarySearch(x,l,mid-1,m);
if (x[mid]<m) return binarySearch(x,mid+1,r,m);
}
return 0;
}
int main(){
int n,q;
cin>>n;
int *x = new int[n];
for(int i=0;i<n;i++){cin>>x[i];}
int t = n;
sort(x,x+t);
cin>>q;
while (q--){
long int m;
cin>>m;
cout<<binarySearch(x,0,t-1,m)<<endl;
}
delete[] x;
return 0;
}