fork download

# include<stdio.h>
int main()
{
	long n,m;
	scanf("%ld",&n);
	scanf("%ld",&m);
 
	longlong b[1000];
	int j = 0;
	int i;
	while( n != -1 || m != -1){
		longlong a[n];
		for( i = 0; i < n; i++){
			scanf("%lld",&a[i]);
		}
		longlong s = 0;
		for( i = 0; i < n; i++){
			s = s + (a[i]*(n-i)*m);
		}
 
		b[j] = s;
		j++;
		scanf("%ld",&n);
	scanf("%ld",&m);
}
	int k;
	for ( k = 0; k < j;k++){
 
	printf("%lld\n",b[k]);
	}
	return 0;
}

prog.c: In function ‘main’:
prog.c:8: error: ‘longlong’ undeclared (first use in this function)
prog.c:8: error: (Each undeclared identifier is reported only once
prog.c:8: error: for each function it appears in.)
prog.c:8: error: expected ‘;’ before ‘b’
prog.c:12: error: expected ‘;’ before ‘a’
prog.c:14: error: ‘a’ undeclared (first use in this function)
prog.c:16: error: expected ‘;’ before ‘s’
prog.c:18: error: ‘s’ undeclared (first use in this function)
prog.c:21: error: ‘b’ undeclared (first use in this function)

Standard output is empty