Double kill

#include <iostream>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>

using namespace std;

struct vector{
    double a,b,c;
};


double len(vector v1){

    double len=sqrt(v1.a*v1.a+v1.b*v1.b+v1.c*v1.c);
    return len;

}


double scalar(vector v1,vector v2){


    return (v1.a)*(v2.a)+(v1.b)*(v2.b)+(v1.c)*(v2.c);

}


vector difference(vector v1,vector v2)
{
    vector v3;
    v3.a=(v1.a-v2.a);
    v3.b=(v1.a-v2.b);
    v3.c=(v1.c-v2.c);
    return v3;
}

double cos(vector v1,vector v2){
    if( abs(len(v1)*len(v2))<1e-9) { return 0; }

    return (scalar(v1,v2)/(len(v1)*len(v2)));

}


bool collinearity(double cos){
    return (abs(cos-1)<1e-9);
}


void insertv(vector *m,int N)
{
    cout << " Insert element of array " <<endl;
    for     (int i=0;i<N;i++) {
        cin >> m[i].a >> m[i].b >> m[i].c;

    }

}

void printv(vector *m,int N)
{
    for (int i=0;i<N;i++)
        cout << m[i].a <<" " <<m[i].b<<" "<<m[i].c <<endl;

    cout << endl;
    //      system("pause");
}





void insertmas(int *mas,int N)
{
    cout << " Insert element of array n " <<endl;
    for     (int i=0;i<N;i++) {
        cin >> mas[i];

    }

}

void printmas(int *mas,int N)
{
    for (int i=0;i<N;i++) { cout <<" "<< mas[i];}

    cout << endl;
    //      system("pause");
}





double max_len(vector *m,int N){
    if(N <= 0) { return 0; }

    double max = len(m[0]);

    for (int i=1;i<N;i++)
        if (len(m[i]) > max)
        {   max=len(m[i]);
    }
    return max;
}


int search(vector *m,int N){
    vector vc;
    cout << endl;
    cout << "Insert a,b,c for your vector which you search";
    cin >> vc.a>>vc.b>>vc.c;
    for (int i=0;i<N;i++)
    {
        if ( (abs(m[i].a-vc.a)<1e-9) && (abs(m[i].b-vc.b)<1e-9) && (abs(m[i].c-vc.c)<1e-9) )
        {return i;
        }
    }
    return -1;

}

vector sum(vector *m,int N){
    vector sum1;
    sum1.a=0;
    sum1.b=0;
    sum1.c=0;
    for (int i=0;i<N;i++)
    {
        sum1.a+=m[i].a;
        sum1.b+=m[i].b;
        sum1.c+=m[i].c;
    }
    return sum1;
}


vector linear_comb(vector *m,int *mas,int N)
{
    vector lin_comb;
    lin_comb.a=0;
    lin_comb.b=0;
    lin_comb.c=0;

    for (int i=0;i<N;i++)
    {
        lin_comb.a+=m[i].a*mas[i];
        lin_comb.b+=m[i].b*mas[i];
        lin_comb.c+=m[i].c*mas[i];
    }

    return lin_comb;
}

int perpendicularity(vector *m,int N,vector v1)
{
    int count=0;
    for (int i=0;i<N;i++)
        if (abs(cos(m[i],v1))<1e-9){count++;}

    return count;
}

void main()
{
    int N;


    vector v1,v2;

    vector v3;
    cout << " Insert a,b,c for v1 ";
    cin >> v1.a>>v1.b>>v1.c;
    /*cout << len(v1);

    cout << " Insert a,b,c for v2 ";
    cin >> v2.a>>v2.b>>v2.c;
    cout << scalar(v1,v2);

    v3=difference(v1,v2);
    cout << "  Difference v1 - v2  " << v3.a<<" " << v3.b<<" " << v3.c<<endl;

    cout <<"collinearity "<<collinearity(cos(v1,v2));


    */
    cout << " Enter elements of array ";
    cin >> N;
    vector *m = new vector[N];
    int *mas = new int[N];
    insertv(m,N);
    cout << endl;
    printv(m,N);
        insertmas(mas,N);
    cout << endl;
    printmas(mas,N);

    cout <<"Max_len "<< max_len(m,N);
    cout<<endl;
    cout<<" Index necessery element "<<search(m,N);
    cout<<endl;
    vector summy=sum(m,N);

    cout<<summy.a<<" "<<summy.b<<" "<<summy.c;
    cout<<endl;
    vector linearry=linear_comb(m,mas,N);
    cout<<linearry.a<<" "<<linearry.b<<" "<<linearry.c;
    cout<<endl;

    cout<<"perpendicularity"<<perpendicularity(m,N,v1);
delete[]m;
delete[]mas;
    system("pause");
}