# C Program for Number of stopping station problem

• Last Updated : 05 Dec, 2018

There are 12 intermediate stations between two places A and B. Find the number of ways in which a train can be made to stop at 4 of these intermediate stations so that no two stopping stations are consecutive?

Examples –

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```Input  : n = 12, s = 4
Output : 126

Input  : n = 16, s = 5
Output : 792
```

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

 `#include ``int` `stopping_station(``int``, ``int``);`` ` `// function to calculate number``// of ways of selecting 'p' non consecutive``// stations out of 'n' stations``int` `stopping_station(``int` `p, ``int` `n)``{`` ` `    ``int` `num = 1, dem = 1, s = p;`` ` `    ``// selecting 's' positions out of 'n-s+1'``    ``while` `(p != 1) {`` ` `        ``dem *= p;``        ``p--;``    ``}`` ` `    ``int` `t = n - s + 1;``    ``while` `(t != (n - 2 * s + 1)) {`` ` `        ``num *= t;``        ``t--;``    ``}`` ` `    ``if` `((n - s + 1) >= s)``        ``printf``(``"%d"``, num / dem);`` ` `    ``else`` ` `        ``// if conditions does not satisfy of combinatorics``        ``printf``(``"not possible"``);``}`` ` `// driver code``int` `main()``{`` ` `    ``// n is total number of stations``    ``// s is no. of stopping stations``    ``int` `n, s;`` ` `    ``// arguments of function are``    ``// number of stopping station``    ``// and total number of stations``    ``stopping_station(4, 12);``}`
Output:
```126
```

Please refer complete article on Number of stopping station problem for more details!

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