Merge branch 'subtraction' into 'master'

Subtraction

See merge request fdai8031/cstools101!3

src/subtraction/subtraction.c

@@ -0,0 +1,6 @@
+#include "subtraction.h"
+int subtract(int a, int b) {
+    if (a==0) return b;
+    if(b==0) return a;
+    else return a - b;
+}

src/subtraction/subtraction.h

@@ -0,0 +1,8 @@
+#ifndef subtraction_H
+#define subtraction_H
+
+int subtract(int a, int b);
+
+#endif
+
+

test/subtraction/subtraction.c

@@ -0,0 +1,11 @@
+#include "unity.h"
+#include "subtraction.h"
+void setUp(){}
+
+void tearDown(){}
+
+void test_subtraction() {
+    TEST_ASSERT_EQUAL_INT(1, subtract(3, 2));
+    TEST_ASSERT_EQUAL_INT(5, subtract(2, -3));
+    TEST_ASSERT_EQUAL_INT(0, subtract(0, 0));
+}