// глобальные константы (значения заданы для примера)
const int n = 10;
const int width = 2;
const int range = 10;
 
void RadixEnumSortOpt(int x[]) {
 
    int source[n] = {0};    
    int count[width][range] = {0};
 
    for (int i = 0; i < n; i++) {
        for (int step = 0, rangepow = 1; step < width; step++, rangepow *= range) {
            int d = (x[i] / rangepow) % range;
            count[step][ d ]++;
        }
    }
 
    for (int step = 0, rangepow = 1; step < width; step++, rangepow *= range) {
        memcpy(source, x, sizeof(source));
 
        int summNum = 0;
        for (int i = 0; i < range; i++) {
            int tmp = count[step][i];
            count[step][i] = summNum;
            summNum += tmp;
        }
 
        for (int i = 0; i < n; i++) {
            int c = (source[i] / rangepow) % range;
            x[ count[step][c] ] = source[i];
            count[step][c]++;
        }
    }
}