1.判断是否是闰年：
#include <stdio.h> int main(void)
{
int year, a;
printf("Please enter the year：\n");
scanf("%d",&year);
if (year % 400 == 0)
a = 1;
else
{
if (year % 4 == 0 && year % 100 != 0)
a = 1;
else
a = 0;
}
if (a == 1)
printf("%d is a leap year\n", year);
else
printf("%d not a leap year\n", year);
return 0;
}
2.判断一个日期是周几，有两种算法
1 #include "stdio.h"
2 int day_of_week1(int y, int m, int d)//使用的是蔡勒公式
3 {
4 if (m < 3)
5 {
6 y--;
7 m += 12;
8 }
9 return ((y%100+(y%100)/4+(y/100)/4-2*(y/100)+(26*(m+1))/10+d-1)%7);
10 }
11
12 int day_of_week2(int y, int m, int d)//
13 {
14 int t[12]={0,3,2,5,0,3,5,1,4,6,2,4};
15 y -= m < 3;
16 return ((y + y / 4 - y / 100 + y / 400 + t[m - 1] + d) % 7);
17 }
18
19 int main(void)
20 {
21 int a = 3, y=2020, m=1, d=1, w1 = 0,w2;
22 printf("%d-%d-%d\n", y, m, d);
23 w1 = day_of_week1(y, m, d);
24 printf("星期%d", w);
25 w2 = day_of_week2(y, m, d);
26 printf("星期%d", w);
27 return 0;
28 }
3.打印心代码（转自一位不知道的大佬）
1 #include "stdio.h"
2 #include <math.h>
3 float f(float x, float y, float z)
4 {
5 float a = x * x + 9.0f / 4.0f * y * y + z * z - 1;
6 return a * a * a - x * x * z * z *z- 9.0f / 80.0f * y * y * z * z * z;
7 }
8 float h(float x, float z)
9 {
10 for (float y = 1.0f; y >= 0.0f; y -= 0.001f)
11 if (f(x, y, z) <= 0.0f)
12 return y;
13 return 0.0f;
14 }
15 int main(void)
16 {
17 for (float z = 1.5f; z > -1.5f; z -= 0.05f)
18 {
19 for (float x = -1.5f; x < 1.5f; x+= 0.025f)
20 {
21 float v = f(x, 0.0f, z);
22 if(v <= 0.0f)
23 {
24 float y0 = h(x,z);
25 float ny = 0.01f;
26 float nx = h(x + ny, z) - y0;
27 float nz = h(x, z+ny) - y0;
28 float nd = 1.0f /sqrtf(nx*nx + ny*ny + nz*nz);
29 float d = (nx+ny-nz) * nd *0.5f + 0.5f;
30 putchar(".:-=+*#%@"[(int)(d*5.0f)]);
31 }
32 else
33 putchar(' ');
34 }
35 putchar(' ');
36 }
37 for (int i = 5; i >0;){}
38 }
4.这个建议自己试试，很好玩。
#include <stdio.h>
#include <stdlib.h>
#define decode(p,r,i,n,t,f) r##f##r##i##t##p
#define puts decode(m,s,t,o,e,y)
int main()
{
puts((char*)(const double[]){1.3553894309652565e+224,6.952439113111912e-308});
return 0;
}
