In the following program we are calculating and displaying the value of nCr. **nCr can also be represented as C(n,r)**

The formula is:

C(n,r) = n! / ( r!(n – r)! ). For 0 <= r <= n. Here ! represents factorial. For example: C(6, 2) = 6! / (2! * (6-2)!) => 720/(2 * 24) => 15

The same calculation we have done in the following program.

#include <stdio.h> int fact(int num); void main() { int n, r, ncr_var; printf("Enter the value of n:"); scanf("%d", &n); printf("\nEnter the value of r:"); scanf("%d", &r); /* ncr is also represented as C(n,r), the formula is: * C(n,r) = n! / ( r!(n - r)! ). For 0 <= r <= n. */ ncr_var = fact(n) / (fact(r) * fact(n - r)); printf("\nThe value of C(%d,%d) is: %d",n,r,ncr_var); } /* This function is used to find the * factorial of given number num */ int fact(int num) { int k = 1, i; // factorial of 0 is 1 if (num == 0) { return(k); } else { for (i = 1; i <= num; i++) { k = k * i; } } return(k); }

**Output:**

Enter the value of n: 5 Enter the value of r: 2 The value of C(6,2) is: 15

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