week14

 step01-1

寫檔

```c

#include <stdio.h>
int main()
{
    FILE * fout = fopen("file.txt", "w+");

     printf("Hello World\n");
    fprintf(fout, "Hello World\n");

    fclose(fout);
}

```c

step01-2

讀檔

```c

#include <stdio.h>
int main()
{
    FILE * fout = fopen("file2.txt", "w+");
    fprintf(fout, "angle1 %d\n", 999);
    fclose(fout);

    char line[200];
    int a;
    FILE * fin = fopen("file2.txt", "r");
    fscanf(fin, "%s %d", line, &a);
    printf("讀到了字串:%s 及整數%d\n", line, a);
    fclose(fin);
}

```c
step01-3
結合前面的寫檔、讀檔, 還有上週的 many TRT 範例
```c
#include <GL/glut.h>
#include <stdio.h> ///為了 printf, fprintf, fopen, fclose ..
float angle[20], oldX=0;
int angleID=0;///0:第0個關節, 1:第1個關節, 2:第2個關節
FILE * fout = NULL;
void myWrite(){
    if(fout==NULL) fout = fopen("file.txt", "w+");
    for(int i=0; i<20; i++){
        fprintf(fout, "%.2f ", angle[i] );
    }
}
void keyboard( unsigned char key, int x, int y){
    if( key=='0' ) angleID=0;///預設是這一個
    if( key=='1' ) angleID=1;
    if( key=='2' ) angleID=2;
    if( key=='3' ) angleID=3;
}///用keyboard的按鍵,來決定等一下 motion()裡要改的 angle[i] 是哪一個
void mouse(int button, int state, int x, int y){///mouse按下去
    oldX = x;
}
void motion(int x, int y){
    angle[angleID] += (x-oldX);
    myWrite();
    oldX = x;
    glutPostRedisplay();
}
```c
step02-1
開新專案
把寫檔的結果重新讀進來，按r鍵可以重播
```c
FILE * fout = NULL, * fin = NULL;
void myWrite(){
    if(fout==NULL) fout = fopen("file.txt", "w+");
    for(int i=0; i<20; i++){
         printf(      "%.2f ", angle[i] );
        fprintf(fout, "%.2f ", angle[i] );
    }
    printf("\n");
    fprintf(fout, "\n");///少了fclose,因為不想要才印一行,就結束。想寫多行一些
}
void myRead(){
    if(fout!=NULL) { fclose(fout); fout=NULL; }///還在讀的檔案要關掉
    if(fin==NULL) fin = fopen("file.txt", "r");
    for(int i=0; i<20; i++){
        fscanf(fin, "%f", &angle[i] );
    }
    glutPostRedisplay();///重畫畫面!!
}
void keyboard( unsigned char key, int x, int y){
    if( key=='r' ){
        myRead();
    }
    if( key=='0' ) angleID=0;///預設是這一個
    if( key=='1' ) angleID=1;
    if( key=='2' ) angleID=2;
    if( key=='3' ) angleID=3;
}
```c
step03-1
timer
```c
#include <GL/glut.h>
#include <stdio.h>
void timer(int t){///t的單位是ms
    ///1000代表1秒, 1500代表1.5秒
    printf("鬧鐘%d, 我起床了\n", t);///起床做事情

    printf("設定下一個鬧鐘\n");
    glutTimerFunc( 2000, timer, t+1);///2秒後
    //printf("設好鬧鐘,再回去睡\n");
}
void display()
{

}
int main(int argc, char**argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE|GLUT_DEPTH);
    glutCreateWindow("week14 timer");

    glutTimerFunc(3000, timer, 0);///3秒後,叫timer()
    glutDisplayFunc(display);
    glutMainLoop();
}
```c