Statistics project

#include<bits/stdc++.h>
using namespace std;
void mergesort(int a[],int i,int j);
void merge(int a[],int i1,int j1,int i2,int j2);
void Boxplot();
int binary_search(int a[],int n);
int linear_search(int a[],int n);
int main()
{
    int press;
    cout<<"For find Box plot or out liner data press 1"<<endl;
    cin>>press;
    if(press==1)
    {
        Boxplot();

    }
}

void Boxplot()
{
    cout<<"Input Arry size"<<endl;
    int size1;
    cin>>size1;
    int A[size1];
    cout<<"Input Number"<<endl;
    for(int i=1; i<=size1; i++)
    {
        cin>>A[i];
    }
    mergesort(A,1,size1);

    int Q1,Q2,Q3,miden;
    if(size1%2!=0)
    {
        Q2=((0+size1)/2)+1;
        miden=A[Q2];
        int half=(0+(Q2-1))/2;
        Q1=(A[half]+A[half+1])/2;
        int half2=((Q2+1)+size1)/2;
        Q3=(A[half2]+A[half2+1])/2;
    }
    else
    {
        int half=(0+size1)/2;
        Q2=(A[half]+A[half+1])/2;
        miden=Q2;
        int half1=(0+half)/2;

        Q1=A[half1];

        int half2=((half+2)+size1)/2;

        Q3=A[half2];

    }
    int low=binary_search(A,size1);
    int high=linear_search(A,size1);
    int IQR=(Q3-Q1);
    int LVT=(Q1-(1.5*IQR));
    int HVT=(Q3+(1.5*IQR));

    cout<<"Q1="<<Q1<<"\n"<<"Q2="<<miden<<"\n"<<"Q3="<<Q3<<endl;
    cout<<"Low value is="<<low<<endl;
    cout<<"LVT is="<<LVT<<endl;
    cout<<"High Value is="<<high<<endl;
    cout<<"HVT="<<HVT<<endl;

}

void mergesort(int a[],int i,int j)
{
    int mid;
    if(i<j)
    {
        mid=(i+j)/2;
        mergesort(a,i,mid);
        mergesort(a,mid+1,j);
        merge(a,i,mid,mid+1,j);

    }
}
void merge(int a[],int i1,int j1,int i2,int j2)
{
    int temp[50];
    int i,j,k;
    i=i1;
    j=i2;
    k=0;
    while(i<=j1&&j<=j2)
    {
        if(a[i]<a[j])
        {
            temp[k++]=a[i++];
        }
        else
        {
            temp[k++]=a[j++];
        }
    }
    while(i<=j1)
    {
        temp[k++]=a[i++];
    }
    while(j<=j2)
    {
        temp[k++]=a[j++];
    }
    for(i=i1,j=0; i<=j2; i++,j++)
    {
        a[i]=temp[j];
    }
}
int binary_search(int a[],int n)
{
    int low=1,high=n,mid;
    int k=1;
    mid=(low+high)/2;
    while(low<=high)
    {
        if(k==mid)
        {
            k=a[mid];
            return k;
        }
        else if(k>a[mid])
        {
            low=mid+1;

        }
        else
        {
            high=mid-1;
        }
        mid=(low+high)/2;
    }
}
int linear_search(int a[],int n)
{
    int max1=0;
    for(int i=1; i<=n; i++)
    {
        if(a[i]>max1)
        {
            max1=a[i];
        }

    }
    return max1;
}