• pgm file format ```cpp

  include

  include

  include

  define DIM 1024

  define DM1 (DIM-1)

  define _sq(x) ((x)*(x)) // square

  define _cb(x) abs((x)(x)(x)) // absolute value of cube

  define _cr(x) (unsigned char)(pow((x),1.0/3.0)) // cube root

unsigned char GR(int,int); unsigned char BL(int,int);

unsigned char RD(int i,int j){

define r(n)(rand()%n)

static char c[1024][1024]; return!c[i][j]?c[i][j]=!r(999)?r(256):RD((i+r(2))%1024,(j+r(2))%1024):c[i][j]; }

unsigned char GR(int i,int j){ static char c[1024][1024]; return!c[i][j]?c[i][j]=!r(999)?r(256):GR((i+r(2))%1024,(j+r(2))%1024):c[i][j]; }

unsigned char BL(int i,int j){ static char c[1024][1024]; return!c[i][j]?c[i][j]=!r(999)?r(256):BL((i+r(2))%1024,(j+r(2))%1024):c[i][j]; } / unsigned char RD(int i,int j){ // YOUR CODE HERE return (char)(_sq(cos(atan2(j-512,i-512)/2))255); } unsigned char GR(int i,int j){ // YOUR CODE HERE return (char)(_sq(cos(atan2(j-512,i-512)/2-2acos(-1)/3))255); } unsigned char BL(int i,int j){ // YOUR CODE HERE return (char)(_sq(cos(atan2(j-512,i-512)/2+2acos(-1)/3))255); } / void pixel_write(int,int); FILE fp; int main(){ fp = fopen(“MathPic.ppm”,”wb”); fprintf(fp, “P6\n%d %d\n255\n”, DIM, DIM); for(int j=0;j<DIM;j++) for(int i=0;i<DIM;i++) pixel_write(i,j); fclose(fp); return 0; } void pixel_write(int i, int j){ static unsigned char color[3]; color[0] = RD(i,j)&255; color[1] = GR(i,j)&255; color[2] = BL(i,j)&255; fwrite(color, 1, 3, fp); }

- 中文宽字符打印
```cpp
#include <iostream>
#include <locale.h>
#include <wchar.h>
#include <stdlib.h>
using namespace std;
int main()
{
   cout << "Hello World"<<endl;
   setlocale(LC_ALL,"zh_CN.UTF-8");
   wprintf(L"%ls\n",L"中文");// mind this 
   return 0;
}