晚安

Week12

檔案寫入和讀取fprintf、fscanf

```
#include <stdio.h>
int main()
{
    FILE * fout = fopen("file.txt", "w");///w:write寫入檔案
    printf("Hello World\n");
    fprintf(fout,"Hello World在檔案裡\n");
}
```

\

#include <stdio.h>
int main()
{
    char line[20];
    ///scanf("%s", line);
    FILE * fin = fopen("file.txt", "r"); ///r:read讀取
    fscanf(fin,"%s",line);
    printf("string get:%s\n",line);
    fscanf(fin,"%s",line);
    printf("string get:%s\n",line);
}

fclose關閉檔案

```

#include <stdio.h>

int main()

{

    int a[10] ={10,20,30,40,50,60,70,80,90,100};

    FILE * fout = fopen("file3.txt","w");

    for(int i=0; i<10; i++){

        fprintf(fout, "%d ", a[i]);

        printf("%d ",a[i]);

    }

    fclose(fout);

    printf("\n");

    int b[10];

    FILE *fin = fopen("file3.txt","r");

    for(int i=0; i<10; i++){

            fscanf(fin, "%d ", &b[i]);

            printf("%d ", b[i]);

    }

    fclose(fin);

}

```

滑鼠事件

茶壺會跟隨鼠標點擊位置移動

```

#include <GL/glut.h>

#include <stdio.h>

float teapotX=0,teapotY=0;

void display()

{

    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

    glPushMatrix();

        glTranslatef(teapotX,teapotY,0);

        glutSolidTeapot(0.3);

    glPopMatrix();

    glutSwapBuffers();

}

void mouse(int button,int state, int x,int y)

{

    teapotX = (x-150)/150.0;

    teapotY = (150-y)/150.0;

    display();

}

int main(int argc, char** argv)

{

    glutInit(&argc, argv);

    glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH);

    glutCreateWindow("week12");

    glutDisplayFunc(display);

    glutMouseFunc(mouse);

    glutMainLoop();

}

```

建立新的檔案儲存滑鼠點擊紀錄

```

#include <GL/glut.h>

#include <stdio.h>

float teapotX=0,teapotY=0;

FILE * fout =NULL;

FILE * fin =NULL;

void display()

{

    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

    glPushMatrix();

        glTranslatef(teapotX,teapotY,0);

        glutSolidTeapot(0.3);

    glPopMatrix();

    glutSwapBuffers();

}

void mouse(int button, int state, int x,int y)

{

    teapotX = (x-150)/150.0;

    teapotY = (150-y)/150.0;

    if(state==GLUT_DOWN){

        if(fout==NULL) fout = fopen("file4.txt", "w");

        fprintf(fout,"%f %f\n",teapotX,teapotY);

    }

    display();

}

void keyboard(unsigned char key,int x,int y)

{

    if(fin == NULL){

        fclose(fout);

        fin = fopen("file4.txt","r");

    }

    fscanf(fin, "%f%f", &teapotX, &teapotY);

    display();

}

int main(int argc, char** argv)

{

    glutInit(&argc, argv);

    glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH);

    glutCreateWindow("week12");

    glutDisplayFunc(display);

    glutMouseFunc(mouse);

    glutMainLoop();

}

```

修改projects - properties - build targets - execution working dir
使生成的程式生成的檔案存在專案檔的通個跟目錄