All of the above represent the number 78. Octal notation means that each digit is worth 8 times as much as the one after. Hexadecimal notation means that each digit is worth 16 times as much as the one after. Hexadecimal notation uses the letters a, b, c, d, e and f to represent the numbers 10, 11, 12, 13, 14 and 15. The ASCII notation gives the ASCII value of the character between the single quotes. In this case the character is N which just happens to be 78 in ASCII.78 // decimal number
0116 // octal number
0x4e // hexadecimal number
'N' // Ascii character
Integers are coded in 2-complement and overflows are silently ignored by Pike. This means that if your integers are 32-bit and you add 1 to the number 2147483647 you get the number -2147483648. This works exactly as in C or C++.
All the arithmetic, bitwise and comparison operators can be used on integers. Also note these functions: