#include _Bool isOdd( int ); int main ( int argc, char *argv[] ) { if ( argc == 2 ) { printf("%s\n", isOdd( atoi( argv[1] ) ) ? "true" : "false" ); return 0; } else { printf("Usage: '%s '\n", argv[0]); return 1; } } _Bool isOdd( int n ) { // Bitwise and with LSB to check if number is odd or even. // LSB == 0 => even // LSB == 1 => odd return n & 1; }