How to add times elapsed from function inside a loop?

I have implemented two ways of doing something inside a loop. I'd like to time them to find out which to keep.

Code:

---

for(int i = 0; i < 1000; i++)
{
    int x = whatever(i);
    foo1(x);
    foo2(x)
}

---

How can I find out the total time of foo1 and foo2? I tried declaring an std::chrono variable outside the for loop and measuring foo1 and food2 with now() but times elapsed can't be added.

You would need to do

Code:

---

t1 = std::chrono::high_resolution_clock::now();
for(int i = 0; i < 1000; i++)
{
    int x = whatever(i);
    foo1(x);
}
t2 = std::chrono::high_resolution_clock::now();
for(int i = 0; i < 1000; i++)
{
    int x = whatever(i);
    foo2(x);
}
t3 = std::chrono::high_resolution_clock::now();

---

Then foo1 takes t2-t1 and foo2 takes t3-t2.