How can I close it ? because case 5 must return to its menu but i cannot put int main(){ inside it because when I will use int main outside case 5 it will just lead to the main menu and not the menu in case 5. I really need it badly.

Code:
#include <stdio.h>
#include <conio.h>
#include<process.h>
#include<dos.h>

void graph();
void foo(){
int choice;
char z,m;

 gotoxy (12,12);textcolor(4+BLINK); cprintf("LOADING:");
 for(m=1;m<=50;m++){
 gotoxy(19+m,12);textcolor(RED);cprintf("");
 }for (z=1;z<=50;z++){
 gotoxy(19+z,12);textcolor(GREEN);cprintf("");
 delay(40);
 }clrscr();
gotoxy(27,3);textcolor(12);cprintf(" ");
gotoxy(40,4);textcolor(12);cprintf(" ");
gotoxy(29,5);textcolor(12);cprintf(" ");

for(int g=1;g<=72;g++){
gotoxy(5+g,2);printf("");
gotoxy(5+g,23);printf("");
}
for(int v=1;v<=20;v++){
gotoxy(5,2+v);printf("ߺ");
gotoxy(78,2+v);printf("");
}
for(int k=1; k<=3;k++){
gotoxy(41,2+k);printf(""); }
for(int p=1;p<=72;p++){
gotoxy(5+p,6);printf("");
}
gotoxy(5,2);textcolor(GREEN);cprintf(" ");
gotoxy(78,2);textcolor(GREEN);cprintf(" ");
gotoxy(5,23);textcolor(GREEN);cprintf("");
gotoxy(78,23);textcolor(GREEN);cprintf("");
gotoxy(41,2);textcolor(GREEN);cprintf("");
gotoxy(5,6);textcolor(GREEN);cprintf("");
gotoxy(78,6);textcolor(GREEN);cprintf("");
gotoxy(41,6);textcolor(GREEN);cprintf("");
for(int l=1;l<=50;l++){
gotoxy(17+l,7);textcolor(YELLOW);cprintf("");
gotoxy(17+l,20);textcolor(YELLOW);cprintf("");
}
for(int n=1;n<=14;n++)
{
gotoxy(18,6+n);textcolor(YELLOW);cprintf("");
gotoxy(67,6+n);textcolor(YELLOW);cprintf("");
}
gotoxy(37,7);textcolor(9);cprintf("  M E N U  ");
gotoxy(30,9);textcolor(6);cprintf("[1] EVEN/ODD IDENTIFIER");
gotoxy(30,11);textcolor(6);cprintf("[2] 1000x NAME MULTIPLIER");
gotoxy(30,13);textcolor(6);cprintf("[3] MULTIPLICATION TABLE");
gotoxy(30,15);textcolor(6);cprintf("[4] TRIANGLE AREA CALCULATOR");
gotoxy(30,17);textcolor(6);cprintf("[5] P A Y R O L L");
gotoxy(29,19);textcolor(6);cprintf(" [6] E X I T ");
gotoxy(24,22);textcolor(4);cprintf("ENTER CHOICE:");
scanf("%d",&choice);
switch(choice)
{
case 1:codes...
case 2:codes.
case 3:codes......
case 4:coes....

case 5:

int main(){

float rate,day,gp,netpay,totald,sss,med,love;int age;
float basic,cola,tax;char employee[20],addr[30],sex[10],bday[8];

clrscr();

char choice;
gotoxy(20,2);textcolor(4);cprintf("Payroll System");
gotoxy(20,4);textcolor(5);cprintf("Select Choices:");
gotoxy(18,6);textcolor(7);cprintf("[1] Add Customer Info");
gotoxy(18,7);textcolor(7);cprintf("[2] Compute Payroll");
gotoxy(18,8);textcolor(7);cprintf("[3] Display Information");
gotoxy(18,9);textcolor(7);cprintf("[4] Exit");
gotoxy(18,10);textcolor(7);cprintf("Enter Choice:");
scanf("%d",&choice);
switch (choice){
case 1:printf("Employee Information\n\n");
    printf("Enter Employee name:");
    scanf("%s",&employee);
    printf("Enter address:");
    scanf("%s",&addr);
    printf("Enter sex:");
    scanf("%s",&sex);
    printf("Enter age:");
    scanf("%d",&age);
    printf("Enter bday:");
    scanf("%s",&bday);main();

case 2:printf("Payroll Input\n:");
    printf("Enter rate:");
    scanf("%f",&rate);
    printf("Enter day:");
    scanf("%f",&day);
    basic=rate*day;
    cola=basic*.02;
    gp=basic+cola;
    sss=gp*.073;
    med=gp*.081;
    love=gp*.092;

    if(gp>=2500){
        tax=gp*.12;}else
        {
        printf("No tax");}

    totald=sss+med+love+tax;
    netpay=gp-totald;main();

case 3:printf("Employee Information\n");
    printf("Employee name is %s\n",employee);
    printf("Employee address %s\n",addr);
    printf("Employee gender%c\n",sex);
    printf("Employee age %d\n",age);
    printf("Employee bday%s\n",bday);
    printf("\n");
    printf("payroll Information\n");
    printf("Rate per day%.2f\n",rate);
    printf("Number of day%.2f\n",day);
    printf("Basic%.2f\n",basic);
    printf("Cola %.2f\n",cola);
    printf("Grosspay%.2f\n",gp);

printf("Tax is%.2f\n",tax);
    printf("Total deduction %.2f\n",totald);
    printf("netpay%.2f\n",netpay);getche();main();

case 4: exit(0);
default:printf("Invalid input");getche();main();
}
getche();graph();
break;
}

getche();


here is the separate code for Case 5:

Code:
#include<stdio.h>
#include<conio.h>
#include<process.h>
float rate,day,gp,netpay,totald,sss,med,love;int age;
float basic,cola,tax;char employee[20],addr[30],sex[10],bday[8];

void main(){
clrscr();

char choice;
gotoxy(20,2);textcolor(4);cprintf("Payroll System");
gotoxy(20,4);textcolor(5);cprintf("Select Choices:");
gotoxy(18,6);textcolor(7);cprintf("[1] Add Customer Info");
gotoxy(18,7);textcolor(7);cprintf("[2] Compute Payroll");
gotoxy(18,8);textcolor(7);cprintf("[3] Display Information");
gotoxy(18,9);textcolor(7);cprintf("[4] Exit");
gotoxy(18,10);textcolor(7);cprintf("Enter Choice:");
scanf("%d",&choice);
switch (choice){
case 1:printf("Employee Information\n\n");
    printf("Enter Employee name:");
    scanf("%s",&employee);
    printf("Enter address:");
    scanf("%s",&addr);
    printf("Enter sex:");
    scanf("%s",&sex);
    printf("Enter age:");
    scanf("%d",&age);
    printf("Enter bday:");
    scanf("%s",&bday);main();break;

case 2:printf("Payroll Input\n:");
    printf("Enter rate:");
    scanf("%f",&rate);
    printf("Enter day:");
    scanf("%f",&day);
    basic=rate*day;
    cola=basic*.02;
    gp=basic+cola;
    sss=gp*.073;
    med=gp*.081;
    love=gp*.092;

    if(gp>=2500){
        tax=gp*.12;}else
        {
        printf("No tax");}

    totald=sss+med+love+tax;
    netpay=gp-totald;main();break;

case 3:printf("Employee Information\n");
    printf("Employee name is %s\n",employee);
    printf("Employee address %s\n",addr);
    printf("Employee gender%c\n",sex);
    printf("Employee age %d\n",age);
    printf("Employee bday%s\n",bday);
    printf("\n");
    printf("payroll Information\n");
    printf("Rate per day%.2f\n",rate);
    printf("Number of day%.2f\n",day);
    printf("Basic%.2f\n",basic);
    printf("Cola %.2f\n",cola);
    printf("Grosspay%.2f\n",gp);

printf("Tax is%.2f\n",tax);
    printf("Total deduction %.2f\n",totald);
    printf("netpay%.2f\n",netpay);getche();main();
    break;
case 4: exit(0);break;
default:printf("Invalid input");getche();main();
}
getche();}