"C Language and Programming" Project 1-4-2-4: Calculate cylinder surface area

1 /*surface area of cylindrical body. CPP:2 Problem Description: Enter the radius of the cylinder R and H, the surface area of the output cylinder S. Hint: π value directly write 3.14159263 */  4   5#include"stdafx.h"  6   7   8 intMain ()9 {  Ten     floatR, H, A;  Oneprintf"Input the radius and height of the cylinder.\n");  Ascanf_s ("%f \%f", &r, &h);  -    -A =2*3.1415926f* R * H +2*3.1415926f* R *R;  the    -printf"\ n the surface area of the cylinder is%f", A);  -    -    +     return 0;  -}

Feelings:

1. The function printf and scanf structures are very similar:

printf ("Output format", variable 1, ..., variable n);

scanf ("Output format",& variable 1,......,& variable n);

As can be seen, the difference between the two grammars lies in the ampersand before the variables. ( Why is this?) )

2.

3.1415926f  

If you discard F, the compiler defaults to double type data, which can result in data loss. (What is the specific loss?) ）

"C Language and Programming" Project 1-4-2-4: Calculate cylinder surface area