Need Programming in C

Write a function, invert(x,p,n) that returns x with the n bits that begin at position p inverted, leaving the others unchanged. For example, if x is 0b 1001, n = 1 and p = 1, invert(x,p,n) would return "0b1011". We can see that 1 bit at position 1 was inverted. Another example, if x is 0b1 1001011, n=3 and p=2, invert(x,p,n) would return "ob11010111