What do you mean by x0 and x1?
If they are variables, you can use array to store values in a continuous manner.

for(int i=0; i<n; i++)

scanf("%d", &x[i]);

Here: x0, x1, x2 etc. will hold same types of values.

If you mean that as a multiplication sign,

while(condition){

value = value x i;

i=i+1;

}

Initialise the values of 'i' and 'values' accordingly.