Merge pull request matthewsamuel95#825 from alokrkmv/patch-1

Create line_count.cpp

Author: matthewsamuel95

Geometry 2D/Lines Intersection/line_count.cpp

@@ -0,0 +1,66 @@
+// CPP program to count number of straight lines
+// with n total points, out of which m are
+// collinear.
+#include <bits/stdc++.h>
+
+using namespace std;
+int nCk(int n, int k)
+{
+
+    int C[k+1];
+    memset(C, 0, sizeof(C));
+
+    C[0] = 1;  // nC0 is 1
+
+    for (int i = 1; i <= n; i++)
+    {
+
+        // Compute next row of pascal triangle
+        // using the previous row
+        for (int j = min(i, k); j > 0; j--)
+
+            C[j] = C[j] + C[j-1];
+    }
+
+    return C[k];
+}
+
+
+int count_Straightlines(int n,int m)
+{
+
+    return (nCk(n, 2) - nCk(m, 2)+1);
+
+}
+
+//Main Function
+int main()
+{
+
+    int n,m;
+
+    while(true)
+    {
+
+         cout<<"Enter total number of points and number of collinear points\n";
+          cin>>n>>m;
+          if(m>n)
+          {
+            cout<<"Number of collinear points cannot exceed total number of points\n";
+            continue;
+          }
+          else
+          {
+
+              break;
+
+          }
+    }
+
+
+
+    cout<<"Number of straight lines that can be drawn are ";
+    cout << count_Straightlines(n, m);
+    return 0;
+
+}