#include<stdio.h>doubleC(int m,int n){double ret =1.0;for(int i =1; i <= n; i++){
ret *=(double)i;}for(int i =1; i <= m; i++){
ret /=(double)i;}for(int i =1; i <=(n-m); i++){
ret /=(double)i;}return ret;}doubleA(int m,int n){double ret =1.0;for(int i =1; i <= n; i++){
ret *=(double)i;}for(int i =1; i <=(n - m); i++){
ret /=(double)i;}return ret;}intmain(){int a, b, k;//第一题
a =5; b =3; k =2;double pa =C(1,3)*C(1,5)/A(2,8);printf("第一题结果是:%f\r\n", pa);//第三题 第一问printf("第三题 第一问:\r\n");double pa1, pa2;for(k =1; k <=9; k++){
pa1 =5*A(k -1,9)/A(k,14);
pa2=5*A(k -1,10)/A(k,15);if(pa1 > pa2){printf("当k = %d 时,pa1 > pa2\r\n",k);}else{printf("当k = %d 时,pa1 < pa2\r\n",k);}}return0;}