Answer 1

Here b = a++ = 7 because post increment first assign value then increase by 1 so here
b = 7 and a will be 8
for a = ++b = 8 because pre increment first increase value then assign. So a = 8 and b = 8
finally c = a + b = 8 + 8 = 16

Answer 2

int a = 7, b = 25;
int c;
b = a++; // b will be 7 since a is post incremented.
a = ++b; // b will become 8 and it is assigned to a, so a is also 8.
c = a + b; // 8+8
cout <<c; // 16