To include a variable in a string in objective-c, you can use string format specifiers with optional length modifiers.
- %i - Integer
- %c - character
- %d - Signed decimal Integer
- %e - Scientific notation using e character
- %E - Scientific notation using E character
- %f - floating point decimal
- %g - the shortest of either %e or %f
- %G - the shorter of %E or %f
- %s - string
- %u - unsigned decimal
Full list: String Format Specifiers - Apple