Merge pull request #1325 from mariaRoxana94/fix-error

Fixed 8XCorrectness_Bugs + 10XBad_Practice_Bugs + 14XDodgy_Code_Bugs

DataStructures/Graphs/BellmanFord.java

@@ -23,7 +23,7 @@ start vertex, end vertes and weights. Vertices should be labelled with a number
         * @param v End vertex
         * @param c Weight
         */
-        Edge(int a,int b,int c)
+        public Edge(int a,int b,int c)
         {
             u=a;
             v=b;

DataStructures/Graphs/MatrixGraphs.java

@@ -127,8 +127,7 @@ class AdjacencyMatrixGraph {
      * @return returns a string describing this graph
      */
     public String toString() {
-        String s = new String();
-        s = "    ";
+        String s = "    ";
         for (int i = 0; i < this.numberOfVertices(); i++) {
             s = s + String.valueOf(i) + " ";
         }