Update class-03.md

school-c-class/class-03.md

@@ -42,8 +42,10 @@ int main() {
   char c = 'I';
 
   printf("%d\n", a);
-  printf("%.2f\n", b);
+  printf("%.2f\n", b); //%.2 sets the floating point precision to 2
   printf("%c\n", c);
+
+  printf("%d %.2f %c \n", a, b, c); // You can try out printing all variables value in a line :)
   return 0;
 }
 /*
@@ -52,5 +54,28 @@ Results:
 15
 10.02
 I
+15 10.02 I
 */
 ```
+## Constant Variables
+```cpp
+const int pressure_pa = 101325;
+// const will assign variable that have fixed value 
+// it cannot be modified until this variable is redeclared
+pressure_pa = 99999; // returns error
+printf("%i", pressure_pa); // "101325" 
+```
+
+## Scanf - user input
+### Ex9
+```cpp
+#include <stdio.h>
+int main() {
+	int input = 10;
+	printf("Please input a number: ");
+	scanf("%d", &input); // retrieves input from user
+	printf("The number is %d\n", input);
+	
+	return 0;
+}
+```