Program in c to find the value of nCr using function?

Answer 1

/*

* Purpose : Calculate the factorial of a number

* Inputs : int x -- the number of interest

* Outputs : x! if x is non-negative, -1 otherwise

*/

int factorial (int x)

{

int x_factorial = x;

if (x > 0)

{

while (x > 1)

{

x_factorial *= --x;

}

return x_factorial;

}

else if (x = 0)

return 1;

else

return -1;

}

/*

* Purpose : Calculate the binomial coefficient nCr

* Inputs : int n -- the set size

* int r -- how many to choose

* Outputs : The binomial coefficient nCr if r is valid, -1 otherwise

*/

int nCr (int n, int r)

{

if (r >= 0 && n >= r)

return factorial(n) / (factorial(r) * factorial(n - r));

else

return -1;

}

Answer 2

C Program to find NCR Value using Recursive Function#include

##include

void main()

{

int n,r,ncr;

clrscr();

printf("Enter the n and r value:");

scanf("%d%d",&n,&r);

ncr=fact(n)/((fact(r))*(fact(n-r)));

printf("n=%d\n",fact(n));

printf("r=%d\n",fact(r));

printf("n-r=%d\n",fact(n-r));

printf("the ncr =%d\n",ncr);

getch();

}

int fact(int a)

{

int c=1,i;

for(i=1;i<=a;i++)

{

c=c*i;

}

return(c);

}

Answer 3

I'll assume that nCr is the shorthand mathematical term: "from n choose r".

If n is a contiguous range of primitive numeric values, then a for loop is preferred:

template<typename T>

void f (const T min, const T max)

{

static_assert (std::is_numeric(T), "non-numeric type in f()");

for (T r=min; r<=max; ++r)

// use r...

}

To achieve the same end using a while loop:

template<typename T>

void f (const T min, const T max)

{

static_assert (std::is_numeric(T), "non-numeric type in f()");

T r=min;

while (r<=max)

// use r...

}

For non-contiguous values, the values are best placed in a sequence container such as a vector. A sequence container is also useful when n is a range of non-numeric values. Again, a for loop is the preferred method:

template<typename T>

void f (const std::vector<T>& n)

{

// from n choose r...

for (auto r : n)

{

// use r...

}

}

To achieve the same end using a while loop, you would need to use the container's iterators:

template<typename T>

void f (const std::vector<T>& n)

{

auto ir = n.begin(); // point to first element

while (ir != n.end())

{

auto r = *ir; // dereference the pointer

// use r...

++ir; // point to next element

}

}