task1

#include <stdio.h>
int main()
{
printf(" O \n");
printf("<H>\n");
printf("I I\n");

return 0;
}

#include <stdio.h>
int main()
{
printf(" O \n");
printf("<H>\n");
printf("I I\n");

printf(" O \n");
printf("<H>\n");
printf("I I\n");
return 0;
}

#include <stdio.h>
int main()
{
printf(" O    O\n");
printf("<H>  <H>\n");
printf("I I  I I\n");


return 0;
}


task2

#include <stdlib.h>
int main()
{
    float a,b,c;

    scanf("%f%f%f",&a,&b,&c);

    if(a+b>c && a+c>b && b+c>a)
        printf("能构成三角形\n");
    else
        printf("不能构成三角形\n");

    system("pause");
    return 0;
}

task3

#include<stdio.h>
int main()
{
	char ans1,ans2;
printf("每次课前认真预习、课后及时复习了没? (输入y或Y表示有,输入n或N表示没有):");
ans1 = getchar(); 
getchar(); 
printf("\n动手敲代码实践了没? (输入y或Y表示敲了,输入n或N表示木有敲) : ");
ans2 = getchar();
if ((ans1=='y'||ans1=='Y')&&(ans2=='y'||ans2=='Y') ) 
printf("\n罗马不是一天建成的, 继续保持哦:)\n");
else
printf("\n罗马不是一天毁灭的, 我们来建设吧\n");
	return 0;
}

task4
#include<stdio.h>
int main()
{
double x, y;
char c1, c2, c3;
int a1, a2, a3;
scanf("%d%d%d", &a1, &a2, &a3);
printf("a1 = %d, a2 = %d, a3 = %d\n", a1,a2,a3);
getchar();
scanf("%c%c%c", &c1, &c2, &c3);
printf("c1 = %c, c2 = %c, c3 = %c\n", c1, c2, c3);
scanf("%lf,%lf", &x, &y);
printf("x = %lf, y = %lf\n",x, y);
return 0;
} 

task5
#include<stdio.h>
#include<math.h>
int main()
{
	int year;
	double second;
	second=1000000000.0;
	year=round(second/60/60/24/365);
	printf("十亿秒约等于%d年\n",year);
	return 0;
}

task6
#include<stdio.h>
#include <math.h>
int main()
{
double x, ans;
while(scanf("%lf", &x) != EOF)
{
ans = pow(x, 365);
printf("%.2f的365次方: %.2f\n", x, ans);
} return 0;
}


#include <stdio.h>
#include<math.h>

int main()
{
    double x,ans;
    
    while(scanf("%lf",&x) !=EOF)
    {
        ans=pow(x, 365);
        printf("%.2f的365次方: %.2f\n",x,ans);
        printf("\n");
    }
    
    return 0;
}


task7

#include<stdio.h>
#include<math.h>
int main()
{
	double C,F;
	while(scanf("%lf",&C) !=EOF){
		F=9.0*C/5+32;
		printf("摄氏温度C=%.2f,华氏温度F=%.2f\n",C,F);
	}
 return 0;
}


task8

#include<stdio.h>
#include<math.h>
int main()
{
	double a,b,c,s,area;
	while(scanf("%lf%lf%lf",&a,&b,&c) !=EOF){
		s=(a+b+c)/2;
		area=sqrt(s*(s-a)*(s-b)*(s-c));
		printf("三角形的面积为%.3f\n",area);
	}
 return 0;
}