solved arraySum and added new problem

src/arraySum.cpp

@@ -0,0 +1,17 @@
+#include <iostream>
+
+using namespace std;
+
+int main(){
+    int n;
+    cout << "Enter number of elements: ";
+    cin >> n;
+    cout << "Enter array elements: " << "\n";
+    int sum = 0;
+    for(int i=0;i<n;i++){
+        int x;
+        cin >> x;
+        sum += x;
+    }
+    cout << "Sum of array = " << sum << "\n";
+}