double 和long int区别在于一个是以指数形式保存,可以保存小数,而long int只能保存整数,不能保存小数点
#include ""double fn( int a , int n )
{
double s = 0;
int i;
for( i = 0 ; i < n ; i++ )
s= s* 10 + a;
return s;
}
int main(void)
{
long int sum= 0;
int a;
long int n;
int i;
printf( "Please inut a:");
scanf( "%d" , &a );
printf( "Please inut n:");
scanf( "%d" , &n );
for( i = 1 ; i <= n ; i++ )
sum += fn( a , i );
printf( "The sum is %ld" , sum );
return 0;
}