//假设公鸡5块钱一只,母鸡3块钱一只,小鸡1块钱三只，需要买一百只鸡，刚好花100元
public class for4 {
    public static void main(String[] args) {
        for (int a = 0; a <= 100; a++) {
            for (int b = 0; b <= 100; b++) {
                for (int c = 0; c <= 100; c++) {
                    if ((a + b + c) == 100 && (5 * a + b * 3 + c / 3) == 100 && c % 3 == 0) {
                        System.out.printf("公鸡:%2d只,母鸡:%2d只,小鸡:%2d只。%n", a, b, c);
                    }
                }
            }
        }
    }
}

执行结果