#include <stdio.h>

int main() {
  
  int h, f;
  
  printf("请输入总头数:");
  scanf_s("%d", &h);
  
  printf("请输入总脚数:");
  scanf_s("%d", &f);
  
  int x, y;
  
  for(x=0; x<=h; x++) {
    y = h - x;
    if(2*x + 4*y == f) {
      break;
    }
  }

  printf("鸡有%d只,兔有%d只\n", x, y);//忽略了条件不符合的情况

  return 0;

}

#include <stdio.h>

int main() {

    int i, j, k, l;
    int count = 0;

    for (i = 1; i <= 9; i++) {
        for (j = 0; j <= 9; j++) {
            for (k = 0; k <= 9; k++) {
                for (l = 0; l <= 9; l++) {

                    if ((i*10000 + j*1000 + k*100 + l*10 + 6) % 3 == 0) {
                        count++;
                    }

                }
            }
        }
    }

    printf("满足条件的5位数共有%d个\n", count);

    return 0;

}

#include <stdio.h>

int main() {
    int x, y, z;
    for (x = 0; x <= 20; x++) {
        for (y = 0; y <= 34; y++) {
            for(z = 0; z <= 100; z++)
            if (5 * x + 3 * y + z == 100 && x + y + z*3 == 100) {
                printf("公鸡: %d只, 母鸡: %d只, 小鸡: %d只\n", x, y, z*3);
            }
        }
    }
    return 0;
}