added logic to ConLiter and Unittest for the function

src/main/c/ConvertMode.c

@@ -12,7 +12,7 @@ double value, result;
 
 char Distance[] = { 'mm', 'cm', 'm', 'km', 'feet/inch', 'miles'};
 char Weight[] = { 'mg', 'g', 'kg', 't', 'pounds'};
-char Fluid[] = { 'ml', 'l' };
+char Fluid[] = { 'ml', 'l' , 'gallon'};
 char Temp[] = { 'celsius', 'fahrenheit' };
 char Speed[] = { 'km/h','mp/h' };
 char Data[] = { 'B', 'KB', 'MB', 'GB', 'TB', 'PT' };
@@ -128,14 +128,62 @@ double getValue(int choice) {
             printf("\nThe convertet result is %dlf %d", result, Speed[endingUnit]);
             break;
 
+        case 8://'ml', 'l'
+            printf("\nEnter what the Unit is starting with (0 ml, 1 l): ");
+            scanf("%d", &startingUnit);
+
+            printf("\nEnter what the value should it be changed to (0 ml, 1 l): ");
+            scanf("%d", &endingUnit);
+
+            result = ConLiter(value, startingUnit, endingUnit);
+
+            printf("\nThe convertet result is %dlf %d", result, Fluid[endingUnit]);
+            break;
         }
     }
 }
+/*
+double ConSpeed(double speed, int startingUnit, int endingUnit) {
+    switch (startingUnit)
+    {
+    case 0: //kmh to x
+        switch (endingUnit)
+        {
+        case 0: //kmh to kmh
+            return speed;
+            break;
 
-double ConLiter() {
+        case 1: //kmh to mph
+            return speed * 0.621371;
+            break;
 
+        default:
+            break;
         }
 
+    case 1: //mph to x
+        switch (endingUnit)
+        {
+        case 0: //mph to kmh
+            return speed * 1.60934;
+            break;
+
+        case 1: //mph to mph
+            return speed;
+            break;
+
+        default:
+            break;
+        }
+
+    default:
+        break;
+    }
+}
+*/
+
+
+
 double ConLiterToGallon() {
 
 }

src/main/c/main_taschenrechner.c

@@ -479,6 +479,44 @@ double ConSpeed(double speed, int startingUnit, int endingUnit) {
     }
 }
 
+double ConLiter(double liter, int startingUnit, int endingUnit) {
+    switch (startingUnit)
+    {
+    case 0: //ml to x
+        switch (endingUnit)
+        {
+        case 0: //ml to ml
+            return liter;
+            break;
+
+        case 1: //ml to l
+            return liter / 1000;
+            break;
+
+        default:
+            break;
+        }
+
+    case 1: //l to x
+        switch (endingUnit)
+        {
+        case 0: //l to ml
+            return liter * 1000;
+            break;
+
+        case 1: //l to l
+            return liter;
+            break;
+
+        default:
+            break;
+        }
+
+    default:
+        break;
+    }
+}
+
 //..
 // graphMode
 void graphMode() {

src/main/c/taschenrechner.h

@@ -71,4 +71,6 @@ double ConTemp(double temp, int startingUnit, int endingUnit);
 
 double ConSpeed(double speed, int startingUnit, int endingUnit);
 
+double ConLiter(double liter, int startingUnit, int endingUnit)
+
 #endif // TASCHENRECHNER_H

src/test/c/test_taschenrechner.c

@@ -73,5 +73,11 @@ void test_ConSpeed(void) {//5 kmh to mph
     TEST_ASSERT_EQUAL(3.10686, result);
 }
 
+void test_ConLiter(void) {//5 l to ml
+    double result = ConTemp(5, 1, 0);
+    TEST_ASSERT_EQUAL(5000, result);
+}
+
+
 
 #endif // TEST