Caesar encryption

src/main/kotlin/Encryption/Caesar.kt

@@ -0,0 +1,34 @@
+package encryption
+object Caesar {
+    fun encrypt(s: String, key: Int): String {
+        val offset = key % 26
+        if (offset == 0) return s
+        var d: Char
+        val chars = CharArray(s.length)
+        for ((index, c) in s.withIndex()) {
+            if (c in 'A'..'Z') {
+                d = c + offset
+                if (d > 'Z') d -= 26
+            }
+            else if (c in 'a'..'z') {
+                d = c + offset
+                if (d > 'z') d -= 26
+            }
+            else
+                d = c
+            chars[index] = d
+        }
+        return chars.joinToString("")
+    }
+
+    fun decrypt(s: String, key: Int): String {
+        return encrypt(s, 26 - key)
+    }
+}
+
+fun main(args: Array<String>) {
+    val encoded = Caesar.encrypt("InteliJ IDEA Community Edition", 10)
+    println(encoded)
+    val decoded = Caesar.decrypt(encoded, 10)
+    println(decoded)
+}

src/test/kotlin/Encryption/CaesarEncTest.kt

@@ -0,0 +1,35 @@
+import encryption.Caesar
+import org.junit.Test
+
+class CaesarEncryptionTest{
+
+    @Test
+    fun testWithKotlinStringAndKey8() {
+        val string = "Kotlin is a powerful programming language"
+        val encoded = Caesar.encrypt(string, 8)
+        assert(Caesar.decrypt(encoded,8)== string)
+
+    }
+    @Test
+    fun testWithIntellIjStringAndKey10() {
+        val string = "InteliJ IDEA Community Edition"
+        val encoded = Caesar.encrypt(string, 10)
+        assert(Caesar.decrypt(encoded,10)== string)
+
+    }
+
+    @Test
+    fun testWithAlgorithmjStringAndKey3() {
+        val string = "Algorithm-Repo"
+        val encoded = Caesar.encrypt(string, 3)
+        assert(Caesar.decrypt(encoded,3)== string)
+
+    }
+
+
+
+
+
+
+
+}