To determine the output of the given program, let's go through each line of code:
- #define ABC 20 - This line defines a macro ABC with the value 20.
- #define XYZ 10 - This line defines a macro XYZ with the value 10.
- #define XXX ABC - XYZ - This line defines a macro XXX which is equal to the value of ABC minus XYZ. Substituting the values, XXX becomes 20 - 10, which is 10.
- void main() - This line declares the main function.
- int a - This line declares an integer variable 'a'.
- a = XXX * 10 - This line assigns the value of XXX multiplied by 10 to the variable 'a'. Substituting the value of XXX, the expression becomes a = 10 * 10, which is 100.
- printf("%d ", a); - This line prints the value of 'a' using the printf function.
Therefore, the output of the program will be "100".
The correct answer is C) 100.