The macro SWAP(a, b) int t; t=a, a=b, b=t; swaps the value of the given two variable.

Step 1: int a=10, b=12; The variable a and b are declared as an integer type and initialized to 10, 12 respectively.

Step 2: SWAP(a, b);. Here the macro is substituted and it swaps the value to variable a and b.

Hence the output of the program is 12, 10.