#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);
}