Function should return value <<<มันErrorอย่างนี้อะคับ ช่วยตรวจทีคับ

#include<stdio.h>
#include<conio.h>
main()
{
clrscr();
char ans;
float sum = 0.0 , expenses , mean = 0.0 ;
int n = 1;
const char line [40] =" ";
printf("\n \n");
printf("* Caculate MEAN Expenses * \n");
printf("%s \n" , line);
do {

printf("\n\n Expenses Course %d =" , n) ;
scanf("%f" , &expenses);
sum = sum + expenses ;
n = n + 1;
printf("\n\n ** caculate agaib y/n =>");
ans = getche();
} while (ans != 'n');
mean = sum / (n-1);
printf("\n %s \n" , line );
printf("\n * Sum Expenses Course = %.2f", sum);
printf("\n * Number Course = %d" , n-1);
printf("\n * Mean Expenses Course = %.2f", mean);
printf("\n\n %s \n", line);
}