>>106
#include <stdio.h>
#include <math.h>
#include <unistd.h>
#define sticklen 0.8
#define PI 3.1416
double x,y;double theta,vtheta,atheta;const double t = 0.2;
void init(void)
{ printf("初期振れ角:");
scanf("%lf",&theta);
vtheta = 0.0;
atheta = -(9.8/sticklen)*sin(PI*theta/180.0);
x = sticklen*sin(PI*theta/180.0);
y = -sticklen*cos(PI*theta/180.0);}
void update(void){
vtheta += atheta*t;
theta += vtheta*t;
atheta = -(9.8/sticklen)*sin(PI*theta/180.0);
x = sticklen*sin(PI*theta/180.0);
y = -sticklen*cos(PI*theta/180.0);}
int main()
{ FILE * fpw; int i;
fpw = popen("gnuplot -persist","w"); init();
fputs("set size square\n", fpw);
fputs("set xrange [-5:5]\n", fpw);
fputs("set yrange [-5:5]\n", fpw);
fprintf(fpw, "set parametric\n");
for (i = 0; i < 200; ++i) {
fprintf(fpw, "plot [0:2*pi] cos(t) / 4.0 + %f , sin(t) / 4.0 + %f\n", x, y);
fprintf(fpw, "pause %f\n", t); update(); }
return 0;}
popenでいいらしいので作った、でもパイプ接続ってわざわざ言われてたならこれじゃまただめだし食らうんだろうなｗ