Tested and experimentet with some more examples

average_biggest.c

@@ -0,0 +1,27 @@
+#include <stdio.h>
+
+int main()
+{
+    float nr, sum, biggest;
+    int ant;
+    sum = 0;
+    biggest = 0;
+    ant = 0;
+
+    printf("Write the numbers.\n");
+    printf("Finish with EOF.\n");
+    while (scanf("%f", &nr) == 1)
+    {
+        ant++;
+        sum += nr;
+        if (nr > biggest)
+        {
+            biggest = nr;
+        }
+    }
+    
+    printf ("Average:    %.3f\n", sum / ant);
+    printf ("Biggest:    %.3f\n", biggest);
+ 
+   return 0;
+}

avg_with_function.c

@@ -0,0 +1,36 @@
+#include <stdio.h>
+
+float max(float x, float y)
+{
+    if (x > y)
+    {
+        return x;
+    }
+    else
+    {
+        return y;
+    }
+}
+
+int main()
+{
+    float number, sum, biggest;
+    int ant;
+    sum = 0;
+    biggest = 0;
+    ant = 0;
+
+    printf("Write the numbers\nFinish with EOF\n");
+    
+    while (scanf("%f", &number) == 1)
+    {
+        ant++;
+        sum += number;
+        biggest = max(biggest, number);
+    }
+
+    printf("Average:    %.2f\n", sum / ant);
+    printf("Biggest:    %.2f\n", biggest);
+
+    return 0;
+}

interest3.c

@@ -0,0 +1,22 @@
+#include <stdio.h>
+
+int main()
+{
+    float cap, want, interest;
+    int year;
+
+    printf("Invested capital: "); scanf("%f", &cap);
+    printf("Want sum: "); scanf("%f", &want);
+    printf("Interest? "); scanf("%f", &interest);
+    
+    year = 0;
+
+    while (cap < want)
+    {
+        year = year + 1;
+        cap = cap * (1 + interest / 100);
+    }
+
+    printf("The capital will have to be at the bank for %d years\n", year);
+    return 0;
+}