What is wrong with this

Question

#include <iostream>
#include <math.h>
using namespace std;

double x1;
double y1;
double x2;
double y2;
double k;

int distance(x1,y1,x2,y2);

int main() {

cin>>x1;
cin>>y1;
cin>>x2;
cin>>y2;

distance(x1,y1,x2,y2);

cout<<" the distance between points "<<"("<<x1<<","<<y1<<")"<<" and "<<"("<<x2<<","<<y2<<")"<< " is "<<k<<endl;

return 0;
}

int distance(x1,y1,x2,y2){
k=pow(pow(x2 - x1,2) + pow(y2 - y1,2),1.0/2);

return k;

}

Answer 1

#include <iostream>
#include <math.h>
using namespace std;

int distance(double x1,double y1,double x2,double y2);

double k; // global variable was not declared

int main() {
double x1;
double y1;
double x2;
double y2;

cin>>x1;
cin>>y1;
cin>>x2;
cin>>y2;
distance(x1,y1,x2,y2); //data types were specified which caused error
cout<<" the distance between points "<<"("<<x1<<","<<y1<<")"<<" and "<<"("<<x2<<","<<y2<<")"<< " is "<<k<<endl;
return 0;
}

int distance(double x1,double y1,double x2,double y2)
{

k=sqrt(pow(x2-x1,2) +(pow(y2-y1,2))); // extra brackets were added

return k;
}

Answer 2

When you pass variables, you do not have specify the type before them. So just call the function like this :

distance(x1,y1,x2,y2);