Can someone please explain what does the (&) mean ? (circled in red above)

this program is in c++.

Given the following function: int func (int & a, int b) { int c: a = 7: b = 9: c = 10: return c * 5: } What would be output if the following code were executed? int a = 12, b = 4, c = 6: a = func (b, c) cout