อยากให้โปรแกรมมันวนรอบการทำงานครับ ช่วยทีครับ

หลังจากที่หายไปหลายอาทิตย์ ผมก็งม ๆ มั่วๆไปแบบของผม
งานต้องส่งวันที่ 4 นี้แล้ว แต่ไปไม่ถึงไหนเลย
ก็คงต้องส่งเท่าที่ทำได้หละครับ T^T


ตอนนี้ติดปัญหาคืออยากให้โปรแกรมมัน วนรอบการทำงาน
อยากให้มันกลับไปที่เมนูคืนครับ

นี้โปรแกรมผมครับ ช่วยทีนะครับ Please

#include <stdio.h>
#include <conio.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

void timee(void)
{
tm*iTDTimeInfo;
time_t rtime;

time(&rtime);
iTDTimeInfo=localtime(&rtime);

printf("\t\t\t\t\t\t\t%s\n",asctime(iTDTimeInfo));
}

void starline1(void)
{
printf("***** **** *** ** * ** *** **** *****\n");
}

void starline2(int k)
{
int o;
for(o=1; o<=k; o++)
printf("*");
printf("\n");
}

main()
{
char choice;
timee();
char* t1="\t\t** Wellcome **\n";
char t2[44]="\t\t** To **\n";
char t3[]="\t\t** Study Room **\n";
char t4[6]={'M','.','3','/','5','\0'};
char t5[10]={'S','r','i','n','d','h','o','r','n'};
char t6[]={'S','c','h','o','o','l','\0'};

printf("\t\t");starline1();
printf("\t\t** (^_^ ) **\n");
printf("%s",&t1[0]);
printf("%s",&t2);
printf("%s",&t3);
printf("\t\t** %s **\n",&t4);
printf("\t\t** %s **\n",&t5);
printf("\t\t** %s **\n",&t6);
printf("\t\t** ( ^_^) **\n");
printf("\t\t");starline1();
getch();
printf("\n\n");starline2(37);
printf("** Please select the Actions menu. **\n");
starline2(37);
printf("a.Results of study\n");
printf("b.Calculator\n");
printf("c.Multiplication table\n");
printf("d.For students to sign\n");
printf("e.Check List for Administrator\n");
printf("f.Add id\n");
scanf("%c",&choice);
clrscr();


switch(choice)
{
case'a':
{
timee();
int number;
printf("[- = > Results of study < = -]\n\n");
printf("Enter your number: ");
scanf("%d",&number);
if(number>0)
{
if(number>=30)
{
printf("You entered the wrong information\n");
}
else
{
int score;
printf("Enter your total score: ");
scanf("%d",&score);
switch(score/10)
{
case 10:
printf("%d is A+\n",score);
break;
case 9:
printf("%d is A\n",score);
break;
case 8:
printf("%d is B\n",score);
break;
case 7:
printf("%d is C\n",score);
break;
case 6:
printf("%d is D\n",score);
break;
default:
printf("%d is F",score);
}
return 0;
}

}
else
{
printf("You entered the wrong information.");
}
return 0;
break;
}

case'b':
{
timee();
double number1 = 0.0;
double number2 = 0.0;
char operation = 0;

printf("[- = > Calculator < = -]\n\n");
printf("\nEnter the calculation\n");
scanf("%lf %c %lf", &number1, &operation, &number2);

switch(operation)
{
case '+':
printf("= %lf\n", number1+ number2);
break;

case '-':
printf("= %lf\n", number1 - number2);
break;

case '*':
printf("= %lf\n", number1 * number2);
break;

case '/':
if(number2 == 0)
printf("\n\n\aDivision by Zero #ERROR!\n");
else
printf("= %lf\n", number1 / number2);
break;

case '%':
if((long)number2 == 0)
printf("\n\n\aDevision by Zero #ERROR!\n");
else
printf("= %ld\n", (long)number1 % (long)number2);
break;

default:
printf("\n\n\aIllegal operation!");
}
return 0;
break;
}

case'c':
{
timee();
printf("\t\t- = > [ Multiplication table ] < = -\n\n");
printf(" 1\t2\t3\t4\t5\t6\t7\t8\t9\t10\t");
printf("\n");
for(int c=1;c<11;c++)
{
printf("%d|",c);
for(int i=1;i<11;i++)
{
printf("%d\t",i*c);
}
printf("\n");
}
return 0;
break;
}

case'd':
{
timee();
FILE *fpt;
char loop = 'Y';

struct terng
{
char name[40];
int number;
float money_daily;
};
struct terng p;

fpt = fopen("D:/dat/terng.txt","w");

if(fpt==NULL)
{
printf("Error..cannot open file!\n");
exit(0);
}

while(loop == 'Y')
{
printf("Enter Name, Number and MoneyDaily => ");
scanf("%s %d %f",p.name,&p.number,&p.money_daily);

fprintf(fpt,"%s %d %f\n", p.name,p.number,p.money_daily);
fflush(fpt);

printf("Add another record [Y/N]: \n");
loop = toupper(getche());
}
fclose(fpt);
printf("\n\n");

return 0;
break;
}

case'e':
{
timee();
FILE *fpt;
struct terng1
{
char name[40];
int number;
float money_daily;
};

struct terng1 h;

fpt = fopen("D:/dat/terng.txt","r");


if(fpt==NULL)
{
printf("Error..cannot open file!\n");
exit(0);
}

printf("Name\t Number MoneyDaily\n");
printf("--------------------------\n");
while(fscanf(fpt, "%s %d %f",h.name,&h.number,&h.money_daily) !=EOF)
printf("%-10s%2d %9.2f\n", h.name,h.number,h.money_daily);

fclose(fpt);
printf("\n");

return 0;
break;
}

case'f':
{
timee();
struct terng2
{
char name[40];
int number;
float money_daily;
};

struct new_terng
{
int id;
char name[40];
int number;
float money_daily;
};

struct terng2 j;
struct new_terng u;

FILE *fpt1,*fpt2;
fpt1 = fopen("D:/dat/terng.txt","r");
fpt2 = fopen("D:/dat/terng.dat","w");

if(fpt1 == NULL || fpt2 == NULL)
{
printf("Error..cannot open file!\n\n");
exit(0);
}

printf("Name\t Number MoneyDaily id\n");
printf("-----------------------------\n");

while(fscanf(fpt1, "%s %d %f", j.name, &j.number, &j.money_daily) != EOF)
{
printf("%-10s %2d %8.2f ", j.name, j.number, j.money_daily);

strcpy(u.name, j.name);
u.number = j.number;
u.money_daily = j.money_daily;

scanf("%d",&u.id);
fprintf(fpt2, "%d %s %d %f\n", u.id,u.name,u.number,u.money_daily);
fflush(fpt2);
}

fclose(fpt1);
fclose(fpt2);

remove("D:/dat/terng.txt");

rename("D:/dat/terng.dat","D:/dat/terng.txt");

printf("\nCopy data to new stucture successful.\n\n");

return 0;
break;
}


}

}