1. Indicate whether the identifiers below are valid or invalid by putting a () for valid and (x) for invalid. Res num Irvigh 2. Fill in the blanks in each of the following. a) Every C program begins execution at the function main b) The left brace begins the body of every function and the right brace ends the body of every function. c) Every statement ends with a(n) semicolon d) The printf standard library function displays information on the screen. e) The escape sequence ln represents the new line. character, which causes the cursor to position to the beginning of the next line on the screen. f) The scanf Standard Library function is used to obtain data from the keyboard. g) The conversion specifier %d is used in a scanf format control string to indicate that an integer will be input and in a printf format control string to indicate that an integer will be output. h) Whenever a new value is placed in a memory location, that value overrides the previous value in that location. This process is said to be destructive i) When a value is read from a memory location, the value in that location is being used but not destroyed; the process is said to be non destructive 3. Complete the following exercises from the C How To Program text. 2.16,2.17,2.18,2.19 and 2.20