HP 35s HP 35s scientific calculator - User Guide - Page 48

Pa r t 3 T Pa r t 2 "Oldest" number Part1 0.0000 Pa r t 3 Pa r t 2 Z Part1 0.0000 Pa r t 3 Pa r t 2 Y Part1 0.0000 Displayed Pa r t 3 X Pa r t 2 Part1 0.0000 Displayed The most "recent" number is in the X-register: this is the number you see in the second line of the display. Every register is separated into three parts: A real number or a 1-D vector will occupy part 1; part 2 and part 3 will be null in this case. A complex number or a 2-D vector will occupy part 1 and part 2; part 3 will be null in this case. A 3-D vector will occupy part 1, part 2, and part 3. In programming, the stack is used to perform calculations, to temporarily store intermediate results, to pass stored data (variables) among programs and subroutines, to accept input, and to deliver output. 2-2 RPN: The Automatic Memory Stack