Question

•

bool test(int a, int& b)

{

bool res = false;

if(a > b)

{

b = a%2;

res = true;

}

return res;

}

int main()

{

int x = 45, y = 43;

test(x, y);

cout << x << " " << y << endl;

return 0;

}

Question: The output of the above code is: ________________

•Write a function that takes an integer as its sole parameter and returns -1, 0 or 1 depending upon whether the integer is odd, zero or even respectively.

•Write a function addFractions that takes as input four integers representing the numerators and denominators of two fractions, adds the fractions, and returns the numerator and denominator of the result. Note that this function should have a total of six parameters. Hint: a/b + c/d = (ad+bc)/bd.

•Write out the contents of the array a after the following code executes:

int a[4];

a[0] = 4;

for(i = 1; i < 4; i++)

{

a[i] = 2*i+2;

if(i > 1)

a[i] = 2*a[i] – a[i-1];

}

Answer 1

1>

To the 'test' function we are passing one argument(x) as call by value and next argument(y) as call by reference. Which mean whatever changes done to y in 'test' will reflect in main function also; but for x it will not. Now in main function we pass 'test(45,43)'. Now a=45 and b =43. if(a>b) becomes true and b=a%2 is executed.45%2 is 1. Now a=45 and b=1 so finally when we print values of x and y, it will print 45 1.

2>

Write a function that takes an integer as its sole parameter and returns -1, 0 or 1 depending upon whether the integer is odd, zero or even respectively.

if(n%2==1)//if remider is 1 after dividing by 2 then number is odd. We use modulo operator
return -1;
else if(n==0)//We use simple equality operator for checking if the number is 0
return 0;
else//if the number is not odd or 0 then number is even
return 1;

3>

Write a function addFractions that takes as input four integers representing the numerators and denominators of two fractions, adds the fractions, and returns the numerator and denominator of the result. Note that this function should have a total of six parameters. Hint: a/b + c/d = (ad+bc)/bd.

#include<iostream>
using namespace std;
void test(int a,int b, int c,int d,int *x,int *y)//a,b,c,d are fractionals and x and y are the addresses of
{                                               // numerator and denominators are stored.
*x=a*d+b*c;
*y=b*d;
}

int main()
{
int *numerator,*denominator,nume,denom;
numerator=&nume;//The variable for storing numerator. the address will be passed to function
denominator=&denom;//The variable for storing denominator. the address will be passed to function
test(1,2,3,4,numerator,denominator);
cout<<nume<<endl<<denom;
}

4>

Write out the contents of the array a after the following code executes:

The output will be 4 4 8 8.

a[0]=4

The for loop starts

i=1

a[1]=2*1+2=4

if condition fails

i=2

a[2]=2*2+2=6

if condition true

a[2]=2*a[2] - a[1]=8

i=3

a[3]=2*3+2=8

if condtion true

a[3]=2*a[3] - a[2]=8

finally we have a[0]=4, a[1]=4, a[2]=8,a[3]=8