refactoring: reduce use of variables in sin and cos function and delete print functions in tests

src/reihen.c

@@ -45,19 +45,14 @@ double sinD(double degrees){
     if (degrees>=360.0){
         degrees = squashDegreesTo360(degrees);
     }
+
     double sum = 0.0;
-    double currvalue;
     double radian = radians(degrees);
-    double power;
-    unsigned long long faculty;
-    for (int i = 0; i <= 9; i++)
-    {
-        currvalue = 1.0;
-        currvalue *= powerD(2*i+1, radian);
-        currvalue /= (double) fac(2*i+1);
-        if(i%2==0) sum += currvalue;
-        else sum -= currvalue;
+
+    for (int i = 0; i <= 9; i++){
+        sum += powerD((double) i, -1.0) * (powerD(2.0*i+1, radian) / fac(2.0*i+1));
     }
+    
     return sum;
 }
 
@@ -65,19 +60,14 @@ double cosD(double degrees){
     if (degrees>=360.0){
             degrees = squashDegreesTo360(degrees);
     }
+
     double sum = 0.0;
-    double currvalue;
     double radian = radians(degrees);
-    double power;
-    unsigned long long faculty;
-    for (int i = 0; i <= 9; i++)
-    {
-        currvalue = 1.0;
-        currvalue *= powerD(2*i, radian);
-        currvalue /= fac(2*i);
-        if(i%2==0) sum += currvalue;
-        else sum -= currvalue;
+
+    for (int i = 0; i <= 9; i++){
+        sum += powerD((double) i, -1.0) * (powerD(2*i, radian) / fac(2*i));
     }
+
     return sum;
 }
 

test/test_reihen.c

@@ -81,11 +81,6 @@ void test_cos(void){
     r3 = cosD(36.97);
     r4 = cosD(180.0);
 
-    printf("%lf\n", r1);
-    printf("%lf\n", r2);
-    printf("%lf\n", r3);
-    printf("%lf\n", r4);
-
     TEST_ASSERT_DOUBLE_WITHIN(0.000001, 0.642787, r1);
     TEST_ASSERT_DOUBLE_WITHIN(0.000001, 0.0, r2);
     TEST_ASSERT_DOUBLE_WITHIN(0.000001, 0.798950, r3);