Expected initializer before 'void'

[deepcool02]

Hey guys im doing a project for my class and im stack on this error for quite a while now. I've been programming with c++ for a week now so there might be more errors. Please help.

#include<iostream>
#include<time.h>
#include<stdlib.h>
#include<string.h>
using namespace std;
int main()
void()
{
void merge(int,int,int);
void merge_sort(int low,int high);
      int pick;
      char data;
      cout<< "Choices:\n";
      cout<< "1. Insertion\n";
      cout<< "2. Selection\n";
      cout<< "3. Merge\n";
      cout<< "4. Bubble\n";
      cout<< "5. Exit\n";
      cout<< "Enter the Number of your Choice: ";
      cin>> pick;
      
      switch(pick)
{
      case 1:
    int i,j,n,temp,a[30];
    printf("Enter the number of elements: ");
    scanf("%d",&n);
    printf("\nEnter the elements: ");
 
    for(i=0;i<n;i++)
    {
        scanf("%d",&a[i]);
    }
 
    for(i=1;i<=n-1;i++)
    {
        temp=a[i];
        j=i-1;
 
        while((temp<a[j])&&(j>=0))
        {
            a[j+1]=a[j];
            j=j-1;
        }
 
        a[j+1]=temp;    
    }
 
    printf("\nSorted list is as follows\n");
    for(i=0;i<n;i++)
    {
        printf("%d ",a[i]);
    }
           break;
      
	  case 2:
               int q,w,e,loc,temmp,min,d[30];
    cout<<"Enter the number of elements: ";
    cin>>e;
    cout<<"\nEnter the elements: ";
 
    for(q=0;q<e;q++)
    {
        cin>>d[q];
    }
 
    for(q=0;q<e-1;q++)
    {
        min=d[q];
        loc=q;
        for(w=q+1;w<e;w++)
        {
            if(min>d[w])
            {
                min=d[w];
                loc=w;
            }
        }
 
        temmp=d[q];
        d[q]=d[loc];
        d[loc]=temmp;
    }
 
    cout<<"\nSorted list is as follows\n";
    for(q=0;q<e;q++)
    {
        cout<<d[q]<<" ";
    }
            break;
      
	  case 3:


int am[50];

{
 int mid;
 if(low<high)
 {
  mid = low + (high-low)/2; //This avoids overflow when low, high are too large
  merge_sort(low,mid);
  merge_sort(mid+1,high);
  merge(low,mid,high);
 }
}
void merge(int low,int mid,int high)
{
 int h,i,j,bm[50],k;
 h=low;
 i=low;
 j=mid+1;

 while((h<=mid)&&(j<=high))
 {
  if(am[h]<=am[j])
  {
   bm[i]=am[h];
   h++;
  }
  else
  {
   bm[i]=am[j];
   j++;
  }
  i++;
 }
 if(h>mid)
 {
  for(k=j;k<=high;k++)
  {
   bm[i]=am[k];
   i++;
  }
 }
 else
 {
  for(k=h;k<=mid;k++)
  {
   bm[i]=am[k];
   i++;
  }
 }
 for(k=low;k<=high;k++) am[k]=bm[k];
}
int main()
{
 int num,i;

cout<<"*****"<<endl;
 cout<<"  merge sort"<<endl;

cout<<"*****"<<endl;
 cout<<endl<<endl;
 cout<<"Please Enter THE NUMBER OF ELEMENTS you want to sort:"<<endl;
 cin>>num;
 cout<<endl;
 cout<<"Now, Please Enter the ( "<< num <<" ) numbers (ELEMENTS):"<<endl;
 for(i=1;i<=num;i++)
 {
  cin>>am[i] ;
 }
 merge_sort(1,num);
 cout<<endl;
 cout<<"So, the sorted list (using MERGE SORT) will be :"<<endl;
 cout<<endl<<endl;

 for(i=1;i<=num;i++)
 cout<<am[i]<<"  ";

 cout<<endl<<endl<<endl<<endl;
return 1;


           break;
      
	  case 4:
           
           int b[50],c,u,p,tempp;
    cout<<"Enter the size of array: ";
    cin>>c;
    cout<<"Enter the array elements: "; 
    
    for(u=0;u<c;++u)
        cin>>b[u];
        
    for(u=1;u<c;++u)
    {
        for(p=0;p<(c-u);++p)
            if(b[p>b[p+1]])
            {
                tempp=b[p];
                b[p]=b[p+1];
                b[p+1]=tempp;
            }
    }
    
    cout<<"Array after bubble sort:";
    for(u=0;u<c;++u)
        cout<<" "<<b[u];
      break;
	  case 5:
      cout <<"Press Enter to Exit";
      default:
      	
      if(data > 5)
      {
      cout<<"Sorry, you've entered the wrong choice. Please try again.";
      cout<<"\nYour Choice: ";
      cin>> pick;
      }
      
      return 0;
}
return 0;
}
}

[AbstractionAnon]

Line 7: This does not belong here. Delete it.

Line 9,10: Forward declarations belong before main(). Not inside it.

Line 8,147: You have two implementations of main()

Line 172: This is going to tell the OS your program terminated abnormally. Nothing after this statement will be executed.

Lines 175-216: Where do these lines belong? They make no sense here. It looks like part of your switch statement, but there is no switch statement in scope.

BTW, your switch statement is way too messy. Your indentation is inconsistent, which makes it very hard to read. I strongly suggest you put each case in its own function, then your switch statement becomes very easy to read:

  switch (var) 
  {
  case 1:  function1();  // Use a more meaningful function name of course
              break;
  case 2:  function2();
              break;
 //  etc
  }