error too few parameters to call even_odd

Quote:

an error saying too few parameters. (void function is required)

Your function

void even_odd(int n) 

expects a parameter, but you call it without any:

even_odd();

Try it like this:

# include <stdio.h>  
# include <conio.h>  
 
void even_odd();
 
int main()  
{  
    int i ;  
    clrscr();
    even_odd();
    getch() ;
    return 0;
}  
 
void even_odd()
{
    int i, n;
    printf("Enter Integer : ") ;  
    scanf("%d", &n) ; 
	
    printf("\nThe odd numbers are :\n\n") ;  
    for(i = 1 ; i <= n ; i = i + 2)  
        printf("%d\t", i) ;

    printf("\n\nThe even numbers are :\n\n") ;  
    for(i = 2 ; i <= n ; i = i + 2)  
        printf("%d\t", i) ;  
}

Your problem is that n is not a parameter but a local variable

void even_odd(int n){

must be replaced by

void even_odd()
    int n;{

Ooops, you also need to change the line before main to

void even_odd();

If you compile as is, Turbo C will tell you that there is another problem because i and n are used in even_odd but declared in main.
the source code with both corrections will look like

# include <stdio.h>
# include <conio.h>

void even_odd();

int main()
{
    clrscr() ;
    even_odd();
    getch() ;
    return 0;
}

void even_odd(){
    int n, i ;
    printf("Enter Integer : ") ;
    scanf("%d", &n) ;
    printf("\nThe odd numbers are :\n\n") ;
    for(i = 1 ; i <= n ; i = i + 2)
        printf("%d\t", i) ;
    printf("\n\nThe even numbers are :\n\n") ;
    for(i = 2 ; i <= n ; i = i + 2)
        printf("%d\t", i) ;
}
</conio.h></stdio.h>