#include <stdio.h>

struct Cell { int row; int col; };
struct Reading { int id; struct Cell cell; int depth; };

int main(void) {
    struct Reading readings[] = {{7, {2, 3}, 18}, {8, {2, 4}, 22}};
    size_t count = sizeof readings / sizeof readings[0];
    for (size_t i = 0; i < count; ++i) {
        printf("%d at %d,%d: %d mm\n", readings[i].id, readings[i].cell.row, readings[i].cell.col, readings[i].depth);
    }
    return 0;
}