adding bin2dec solution

Projects/1-Beginner/bin2dec.java

@@ -0,0 +1,39 @@
+/**
+ * 
+ */
+import java.util.*;
+import java.lang.Math;
+/**
+ * @author safouene
+ *
+ */
+public class bin2dec {
+
+	/**
+	 * @param args
+	 */
+	public static boolean arrondi(String s) {
+		boolean b = true;
+		for (int i = 0; i < s.length(); i++) {
+			if(s.charAt(i) != '0' && s.charAt(i) != '1') { return false;}
+		}
+		return true;
+	}
+
+	public static void main(String[] args) {
+		System.out.println("Type a binary number");
+        Scanner sc = new Scanner(System.in);
+        String binNumber = sc.nextLine();
+        while (!arrondi( binNumber )) {
+        	System.out.println("Error, type again");
+        	binNumber = sc.nextLine();
+        	}
+        int decNumber = 0;
+        int l = binNumber.length();
+        for (int i = 0; i < l; i++) {
+        	decNumber += Character.getNumericValue(binNumber.charAt(i)) *Math.pow(2, l-i);
+        }
+        System.out.print(decNumber);
+	}
+
+}