CS1010E Programming Methodology Tutorial 4 Modular Programming with Functions C14,A15,D11,C08,C11,A02

Question 1 a)What is the output ? LineMainFunc1Console 4X = X = 0X = 1 12X = 0X = 11 7X = 00

Question 1 What is the output? LineMainFunc2Console 4X=1,Y= X=1,Y=2Num1= 1, Num2= 2 12X=1,Y=2Num1= 100, Num2= 2 13X=1,Y=2Num1= 100, Num2= X=1,Y=2Num1= 100, Num2= X=1,Y=2Num1=2,Num2=1 12X=1,Y=2Num1= 200, Num2= 1 13X=1,Y=2Num1= 200, Num2= X=1,Y=2Num1= 200, Num2= X=1,Y=21 2

Question 2 Random Function Rand() rand() returns a pseudo random Integer rand() number needs a SEED srand(int seed) reset SEED to be seed If srand() is not called, rand() uses default Create random INTEGER in [a, b]Create random number in [0, 1] How to generate random number in arbitrary interval ? How to generate other distributions ?

Question 2 Compare the two codes : The difference is where the srand(seed) is called For code 1, different random number is generated For code 2, the random number is always the same Because seed is reset in every iteration

Question 3

Storage Class and Scope Global variables: outside functions Global Variables are consider BAD !! Local variables: within functions

Storage classes - Static Static can also be defined within a function Static variable Is initialized at compilation time and retains its value between calls int main(void) { func(); } void func(){ static int count = 0; count++; printf("%d",count); } The function called with the same parameter may return different result

Some Questions from Past Year Paper Note that “%f” by default outputs to 6 decimal places!

Some Questions from Past Year Paper When evaluation, anything not 0 is TRUE, 0 is FALSE When output, TRUE is 1, FALSE is 0

Some Questions from Past Year Paper When use ++x, you increment before you fetch When use x++, you increment after fetch

Some Questions from Past Year Paper Be careful with the stopping condition

Some Questions from Past Year Paper Don’t get confused by the indentation!

Some Questions from Past Year Paper Macron is always direct substitution! Z=((++x) >= (y++)? (++x): (y++));

Some Questions from Past Year Paper (D) X = I = 0 cannot be used in variable declaration

Some Questions from Past Year Paper (A) Short-cut evaluations

Some Questions from Past Year Paper (B) Careful with (int) coercion

Some Questions from Past Year Paper (E) Direct substitution!