given that c is integer ----------> let c stored at memory location 100 with the value 4
given that b is pointer to c ----------> let b stored at memory location 200 with the value 100
given that a is pointer to b ----------> let a stored at memory location 300 with the value 200
therefore c is integer, b is a pointer to integer, a is a pointer to integer pointer...
for accessing value at c you have three methods c, *b, **a
in C, parameters are call by value only.... ===> just copy the values
f ( int x, int *py, int **pz ) ---- x is integer, py is a pointer and pz is a pointer to integer pointer
∴ x=4, py=100,pz=200
**pz+=1; ===> **pz=**pz+1 ===> **pz = ( (**pz) + (1) ) [ using precedence of operator ]
**pz = ** (200) = * (100) = value at 100, if it is left side of = operator it is storing the value, else it is right side of = operator it retrieve the value
∴ storing value of (memory address 100) = retrieving value of (memory address 100) + 1 ===> c=c+1 ==> c=4+1 ==> c=5
*py+=2; ===> *py=*py+2 ===> *py = ( (*py) + (1) ) [ using precedence of operator ]
*py = * (100) = value at 100
∴ storing value of (memory address 100) = retrieving value of (memory address 100) + 2 ===> c=c+2 ==> c=5+2 ==> c=7
x+=3; ===> x=x+3 ===> x = ( (x) + (3) ) [using precedence of operator] ==> x=4+3 ===> x=7
return x+*py+**pz ===> return ( (x)+(*py)+(**pz) ) ===> return ( 7+7+7 ) ===> return (21)
∴ Answer is 21
