Is it expensive to compute vector size in for loops, each iteration?

Question

Does the c++ compiler take care of cases like, buildings is vector:

for (int i = 0; i < buildings.size(); i++) {}

that is, does it notice if

Answer 1

buildings.size() will likely be inlined by the compiler to directly access the private size field on the vector class. So you shouldn't separate the call to size. This kind of micro-optimization is something you don't want to worry about anyway (unless you're in some really tight loop identified as a bottleneck by profiling).