move exercises, lecture examples, labs into subfolders

Exercises/C8/ex7.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <math.h>
+
+int main() {
+	int rc; // used to check return codes of scanf
+	float radius, height;
+
+	printf("Enter radius: ");
+	rc = scanf("%f", &radius);
+	// scanf returns number of scanned items. If input is invalid then 0 values will have been scanned.
+	if (rc != 1) {
+		printf("Please enter an positive real integer or decimal\n");
+		return 1;
+	}
+
+	printf("Enter height: ");
+	rc = scanf("%f", &height);
+	// scanf returns number of scanned items. If input is invalid then 0 values will have been scanned.
+	if (rc != 1) {
+		printf("Please enter an positive real integer or decimal\n");
+		return 1;
+	}
+
+	printf("Surface area: %f\n", 2*M_PI*radius*radius + 2*M_PI*radius*height);
+}