#include bool isEven( int n ) { return n % 2 == 0; } /* START: Fig02_11.txt*/ long pow( long x, int n ) { /* 1*/ if( n == 0 ) /* 2*/ return 1; /* 3*/ if( n == 1 ) /* 4*/ return x; /* 5*/ if( isEven( n ) ) /* 6*/ return pow( x * x, n / 2 ); else /* 7*/ return pow( x * x, n / 2 ) * x; } /* END */ // Test program int main( ) { cout << "2^21 = " << pow( 2, 21 ) << endl; cout << "2^30 = " << pow( 2, 30 ) << endl; return 0; }