Update example solution task 4.07 to fully comply with task specification

ch_4/task_07/main.c

@@ -55,15 +55,15 @@ int main (void) {
         /* Read in the user's input */
         scanf("%lf",&cash);
         /* Check if input was valid */
-        if (cash < 0) {
+        if (cash < 0.1) {
             /* Number has to be greater than 0 */
-            printf("The entered deposit is less than 0!\n");
+            printf("The entered deposit is too less!\n");
         }else if (cash > MONEY_MAX) {
             /* Number entered is too big */
             printf("The entered deposit is too big!\n");
         }
     /* Repeat when a invalid number was entered */
-    } while ((cash < 0) || (cash > MONEY_MAX));
+    } while ((cash < 0.1) || (cash > MONEY_MAX));
     
     /*
      * From this moment on we calculate with (int), because ...