Bài tập tổng hợp các hàm bữa thứ sáu !!!!

#include<stdio.h>
#include<conio.h>
void nhapmang(int a[], int &n)
{
do
{
printf("\nBan muon thuc hien voi bao nhieu so nao ? \n");
printf("\nMoi ban nhap vao: ");
scanf("%d",&n);
for (int i=0;i<n;i++)
{
printf("\nNhap so thu %d vao:",i);
scanf("%d",&a[i]);
}
}
while ((n<0) || (n>10));
}
void xuat (int a[],int &n)
{
for (int i=0;i<n;i++)
printf("%5d",a[i]);
}
int tong (int a[],int n)
{
int t=0;
for (int i=0;i<n;i++)
t=t+a[i];
return t;
}
void max (int a[],int &n,int &l)
{
l=a[0];
for (int i=1;i<n;i++)
if(l<a[i]) l=a[i];
}
int timkiem (int a[], int n, int x)
{
int vt=0;
while (vt<n && a[vt] != x)
vt++;
if (vt<n)
return vt;
else
return -1;
}
int tongchan(int a[], int n)
{
int tc=0;
for (int i=0;i<n;i++)
if(a[i]%2==0) tc+=a[i];
return tc;
}
void xeptang(int a[],int n)
{
int i,j,bp;
for (i=0;i<n;i++)
{
for(j=i+1;j<n;j++)
{
if(a[i]>a[j])
{
bp=a[i];
a[i]=a[j];
a[j]=bp;
}
}
}
}
int kt(int a[],int n)
{
int dem=0,tn=0;
for (int i=0;i<n;i++)
{
for (int j=2;j<a[i];j++)
if (a[i]%j==0) dem+=1;
if (dem == 0) tn=tn+a[i];
dem=0;
}
return tn;
}
void them(int a[],int &n, int vt,int s)
{
if(vt>=0 && vt<= n)
{
for (int i=n;i>vt;i--)
a[i]=a[i-1];
a[vt]=s;
n++;
}
}
void main ()
{
int a[10],n,kq,l,b,x,i,vt,s,chon;
char yn;
printf("\nDay la chuong trinh thuc hien theo chuc nang !!!!");
printf("\nChuc nang nay chi thuc hien tren mang !!!!");
printf("\nNhan y:Dong y su dung \n Nhan n:Khong dong y");
printf("\nHay nhap su lua chon cua ban: ");
scanf("%c",&yn);
switch (yn)
{
case 'n':
{
printf("Nhan ENTER de co the ket thuc chuong trinh\n");
printf("Cam on ban da su dung");
}
break;
case 'y':

{
do
{
printf("\nHay chon su lua chon cua ban di nao ????");
printf("\n 1: Tong cac gia tri trong mang \n 2:Tinh tong cac so chan trong mang \n 3:Tim so lon nhat trong mang \n 4:Ban muon biet so da nhap nam o vi tri thu may \n 5:Tong cac so la so nguyen to \n 6:Xep cac so theo thu tu tang dan \n 7:Them mot so trong mang \n 8:Nhan so 8 de ket thuc chuong trinh \n Nhap su lua con cua ban vao day van nhan ENTER di");
scanf("%d",&chon);

switch(chon)
{
case 1:
{
nhapmang(a,n);
kq=tong(a,n);
printf("\nTong ca phan tu trong mang la: %d",kq);
}
break;
case 2:
{
nhapmang(a,n);
printf("\nTong cac so chan trong mang la: %d",tongchan(a,n));
}
break;
case 3:
{
nhapmang(a,n);
max(a,n,l);
printf("\nSo lon nhat trong mang la: %d",l);
}
break;
case 4:
{
nhapmang(a,n);
printf("\nNhap so ban muon tim kiem vao:");
scanf("%d",&x);
if (timkiem(a,n,x)==-1) printf("\nKhong tim thay gia tri can tim");
else printf("\nVi tri cua so do la %d ",timkiem(a,n,x));
}
break;
case 5:
{
nhapmang(a,n);
printf("\nTong ket qua cac so nguen to trong mang la: %d",kt(a,n));
}
break;
case 6:
{
nhapmang(a,n);
xeptang(a,n);
printf("\nMang duoc xep theo tang dan sau day");
xuat(a,n);
}
break;
case 7:
{
nhapmang(a,n);
printf("\nBan muon chen vao vt so may ? ");
printf("\nNhap vi tri vao: %d");
scanf("%d",&vt);
printf("\nNhap con so muon chen vao : %d");
scanf("%d",&s);
them(a,n,vt,s);
xeptang(a,n);
xuat(a,n);
}
break;
case 8:printf("\nNhan ENTER de ket thuc chuong trinh");
break;
}

}
while (chon <;
}
}
getch();
}