Возврат в меню после окончания работы в графическом режиме - C (СИ)

#include <stdio.h>
#include <graphics.h>
#include <conio.h>
#include <math.h>
#include <stdlib.h>
struct toch {int x,y;};
const int n=20;
void zavdanya()
{
   system("cls");
   printf("Student grupy KM-145, LOPATIN VLADISLAV STANISLAVOVICH");
   printf("\nKursova robota");
   printf("\nStvorenya programnogo kompleksu movamy programuvanya Pascal ta C");
   printf("\nIndividualne zavdanya #6");
   getch();
}
void umova1()
{
   system("cls");
   printf("Vikonati tabuliaciy parametrichni zadanoi funkcii");
   printf("\n(Ravlik Paskalya(kardioida)), zapisati ii u fail ta vivesti iogo na ekran.");
   printf("\nPobuduvati i vivesty na ekran monitora graphik ciei funkcii:");
   printf("\nx=a*sqr(cos(t))+b*cos(t)");
   printf("\ny=cos(t)*sin(t)+b*sin(t)");
   printf("a,b >0; t (0;2*pi)");
   getch();
}
void umova2()
{
   system("cls");
   printf("'  U file zadano koordinaty tochok. Kilkist yakih");
   printf("\nbilsha desati. Vivesti na ekran 10 tochok, u yakih vodstan");
   printf("\n'vid centra ekranu naymensha. Provesti cherez ci tichki lamanu");
   printf("\nliniyu. Okremim kolorom vidility naykorotshiy ta");
   printf("\nTretim kolorom vidility ti trikutniki, shcho znahodyatca v");
   printf("\nnaydovshiy vidrizki lamanoi");
   getch();
}
void menugolovne()
{
system("cls");
printf("1-Zavdanya");
printf("\n2-Zavdanya #1");
printf("\n3-Zavdanya #2");
printf("\n4-Exit");
printf("\n\nZrobit budi-lasca sviy vibir: ");
}
void menuzavdanya1()
{
system("cls");
printf("1-Umova zavdanya");
printf("\n2-Tabulyacia functcii");
printf("\n3-Vivedennia tabuliacii na ekran");
printf("\n4-Grafik functcii");
printf("\n5-Nazad");
printf("\n\nZrobit budi-lasca sviy vibir: ");
}
void menuzavdanya2()
{
system("cls");
printf("1-Umova zavdanya");
printf("\n2-Vmist faily");
printf("\n3-Vivedennia tochok");
printf("\n4-Nazad");
printf("\n\nZrobit budi-lasca sviy vibir: ");
}
void vvod(int a,int b, int n)
{
float t,c,tabx,taby; FILE *fil;
   fil=fopen("tabulyacia.txt","wt");
   system("cls");
   c=fabs((2*M_PI)/(n-1));
   t=0;
   fprintf(fil,"|---------------|-------------|");
   fprintf(fil,"\n|       x       |      y      |");
   fprintf(fil,"\n|---------------|-------------|");
   while (t<=2*M_PI)
      {
    tabx=a*pow(cos(t),2)+b*cos(t);
    taby=cos(t)*sin(t)+b*sin(t);
    fprintf(fil,"\n|  x=%7.3f    |  y=%7.3f  |",tabx,taby);
    fprintf(fil,"\n|---------------|-------------|");
    t = t + c;
      }
   printf("Tabulyacia i zapis u file zaversheno");
   getch();
   fclose(fil);
}
void vivod()
{
FILE *fil; char s[30];
system("cls");
fil=fopen("tabulyacia.txt","r");
while (!feof(fil))
{
fgets(s,30,fil);
printf("%s",s);
}
getch();
fclose(fil);
}
void graphik(int a,int b)
{
float tabx,taby,t,y; int k;
system("cls");
int gd=DETECT,gm;
initgraph(&gd,&gm," ");
t=0;
setcolor(2);
line(320,0,320,480);
line(0,240,640,240);
k=0;
while (k<=640)
{
line(k,237,k,243);
k=k+10;
}
k=0;
while (k<=480)
{
line(318,k,322,k);
k=k+10;
}
while (t<2*M_PI)
{
tabx=a*pow(cos(t),2)+b*cos(t);
taby=cos(t)*sin(t)+b*sin(t);
putpixel(tabx*10+320,taby*10+240,2);
t=t+0.01;
}
getch();
closegraph();
}
void vmistft()
{
system("cls");
FILE *f; int l; struct toch at;
f=fopen("koord.txt","r");
l=1;
while (!feof(f))
{
fscanf(f,"%d %d",&at.x,&at.y);
printf("Tochka %d: (%d;%d)\n",l,at.x,at.y);
l++;
}
getch();
}
void tochka()
{
struct toch at; float vid,min,mint,maxt;
int l,k,t,i,j,x,y;
FILE *f;
float vids[99],vidst[99],rezul[9];
int koordx[99],koordy[99],koordx1[9],koordy1[9];
k=0;
f=fopen("koord.txt","r");
while (!feof(f))
{
fscanf(f,"%d %d",&at.x,&at.y);
vid=sqrt(at.x*at.x+at.y*at.y);
vids[k]=vid;
koordx[k]=at.x; koordy[k]=at.y;
k++;
}
l=0;
while (l<k)
{
vidst[l]=vids[l];
l++;
}
t=0;
while (t<10)
{
l=0;
min=9999;
while (l<k)
{
if (min>vidst[l]) min=vidst[l];
l++;
}
l=0;
while (l<k)
{
if (vidst[l]==min) vidst[l]=9999;
l++;
}
rezul[t]=min;
t++;
}
int gd=DETECT,gm;
initgraph(&gd,&gm," ");
j=0;
setcolor(2);
line(320,0,320,480);
line(0,240,640,240);
while (j<10)
{
l=0;
while (l<k) {
if (vids[l]==rezul[j]) { koordx1[j]=koordx[j];
koordy1[j]=koordy[j];
circle(koordx[j]*20+320,abs(koordy[j]*20-240),2); }
l++;
}
j++;
}
j=0;
while (j<=640)
{
line(317,j,323,j);
line(j,237,j,243);
j=j+20;
}
j=0;
while (j<10)
{
if (j==9) line(koordx1[j]*20+320,abs(koordy1[j]*20-240),koordx1[0]*20+320,abs(koordy1[0]*20-240)); else
line(koordx1[j]*20+320,abs(koordy1[j]*20-240),koordx1[j+1]*20+320,abs(koordy1[j+1]*20-240));
j++;
}
getch();
fclose(f);
closegraph();
}
int main(void)
{
int a,b,p,n;
poch:
system("cls");
menugolovne();
scanf("%d",&p);
switch(p)
{
 case 1: { zavdanya(); goto poch; }
 case 2: { m1: menuzavdanya1();
       scanf("%d",&p);
       switch(p)
       {
         case 1: { umova1(); goto m1; }
         case 2: {system("cls");
           printf("Vvedite a="); scanf("%d",&a);
           printf("Vvedite b="); scanf("%d",&b);
           printf("Vvedite kilkist n="); scanf("%d",&n);
           vvod(a,b,n); goto m1; }
         case 3: { vivod(); goto m1; }
         case 4: {system("cls");
           printf("Vvedite a="); scanf("%d",&a);
           printf("Vvedite b="); scanf("%d",&b);
           graphik(a,b); goto m1; }
         case 5: { goto poch; }
        }
 }
case 3: { m2: menuzavdanya2();
       scanf("%d",&p);
       switch(p)
         {
          case 1: { umova2(); goto m2; }
          case 2: { vmistft(); goto m2; }
          case 3: { tochka(); goto m2; }
          case 4: { goto poch; }
          } }
case 4: { exit(1); }
}
getch();
}