add basic, strcmp

Author: yxjiang

src/main/java/algorithm/basic/Strcmp.java

@@ -0,0 +1,37 @@
+package algorithm.basic;
+
+public class Strcmp {
+  
+  /**
+   * If s1 > s2, return 1, if s1 == s2, return 0, else return -1
+   * @param s1
+   * @param s2
+   * @return
+   */
+  public int strcmp(String s1, String s2) {
+    int pos1 = 0;
+    int pos2 = 0;
+    
+    while (pos1 < s1.length() || pos2 < s2.length()) {
+      if (pos1 == s1.length()) { // s1 reaches the end
+        return -1;
+      }
+      if (pos2 == s2.length()) { // s2 reaches the end
+        return 1;
+      }
+      if (s1.charAt(pos1) < s2.charAt(pos2)) {
+        return -1;
+      }
+      else if (s1.charAt(pos1) > s2.charAt(pos2)) {
+        return 1;
+      }
+      else {
+        ++pos1;
+        ++pos2;
+      }
+    }
+    
+    return 0;
+  }
+
+}

src/test/java/algorithm/basic/TestStrcmp.java

@@ -0,0 +1,28 @@
+package algorithm.basic;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+public class TestStrcmp {
+  
+  @Test
+  public void testStrcmp() {
+    Strcmp cmp = new Strcmp();
+    String s11 = "abcdedf";
+    String s12 = "abcdedf";
+    
+    assertEquals(0, cmp.strcmp(s11, s12));
+    
+    String s21 = "abcdef";
+    String s22 = "abcdefg";
+    
+    assertEquals(-1, cmp.strcmp(s21, s22));
+    
+    String s31 = "babcdef";
+    String s32 = "aabcdefg";
+    
+    assertEquals(1, cmp.strcmp(s31, s32));
+  }
+
+}