Inserting one element in the right position in a sorted array using binary search to find the right position,,,but having a run time error

this is my code

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#include <stdio.h>

void show(int*,int);
int sort (int*,int);
int BinSearch(int[],int,int);
int Insertelem(int*,int,int,int*);

int main(void)
{
    int array[100]={15,30,40,10,25,5,35,20,45};
    int len=9;//length
    int *pos=0;//position
    int elem=0;//element
    int ok=0;

    printf("array : ");
    show(array,len);
    sort(array,len);
    printf("array after sorting : ");
    show(array,len);
    printf("enter the number you want to add :");
    scanf("%d",&elem);
    *pos=BinSearch(array,elem,len);
    ok=Insertelem(array,len,elem,pos);
    show(array,len);

    return 0;
}
void show(int *array,int len)//print the array
{
    for(int i=0;i<len;i++)
    {
        printf("%d,",array[i]);
    }
    printf("\n");
    }
int sort(int *array,int len)//sort the array
{
    int help=0;
    for(int i=len-1;i>0;i--)
    {
        for(int j=0;j<i;j++)
        {
            if(array[j]>array[j+1])
            {
                help=array[j];
                array[j]=array[j+1];
                array[j+1]=help;
            }
        }
    }
    return *array;
}
int BinSearch(int array[100],int elem,int len)//searching for the position
{
    int first=1;
    int last=len-1;
    int middle=(first+last)/2;
    int pos;

    while(first<=last)
    {
        if(elem<array[middle])
        {
            last=middle-1;
            middle=(first+last)/2;
        }
        else if(elem>array[middle])
        {
            first=middle+1;
            middle=(first+last)/2;
        }
        else if(elem==array[middle])
        {
            break;
        }

    }
    pos=array[middle]+1;
    return pos;
}
int Insertelem(int *array,int len,int elem,int *pos)//inserting the element
                                                    //in the right position 
{
    len++;
    for(int i=len-1;i>*pos+1;i--)
    {
        array[i+1]=array[i];
    }
    elem=array[*pos];
    return *array;
}

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note : there is no compiler error

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I think the problem is in the binsearch function or Insertelem function because I tested all other functions and they are working as expected

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when I run this code it works so good until the user enter the element he wont and the program just crash