Average number of characters per line

#include<stdio.h>
#include<conio.h>
int linei(void);
main()
{
      int n,i=0,sum=0;
      float avg;
      printf("Enter the text.\n\n");
      while((n=linei())>0)
      {
                              sum+=n;
                              ++i;
      }
      avg=(float)sum/i;
      printf("\nAverage number of characters per line: %f",avg);
getch();
}

int linei(void)
{
    char line[80];
    int i=0;
    while((line[i]=getchar())!='\n')
                                        ++i;
    return(i);
}