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Divide a triangle into n triangles

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How to divide a triangle into n equal area triangles ?
See Solution: Divide a triangle into n triangles

For any triangle its area can be calculated using the formula base * height/2. So we can divide a triangle into n triangles of equal area by simply dividing the base into n equal parts.

Explanations :
For example to divide the triangle in the image below into 4 equal triangles, we can simply divide its base of 8cms to 4 equal parts of 2cms each and form the 4 triangles of equal area.

divide a triangle into n triangles

divide a triangle into 4 triangles of equal area

Swap two integer variables

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How to swap two integer variables without using the third variable ?
See Solution: Swap two integer variables

I know three solutions, comment if you know more 🙂

Solution 1:

x = x+y;
y  = x-y;
x  = x-y;

Solution 2:

y = 2*((x+y)/2) – (x =y);

Solution 3:

x = x^y;
y = x^y;
x = x^y;

Note: However solution 1 & 2 has problem of overflow doing addition of two integers might overflow. But solution 3 will not have any such problem

How to measure 4 gallon of water

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How to measure exactly 4 gallon of water from 3 gallon and 5 gallon jars, Given, you have unlimited water supply from a running tap.

It was also solved by Bruce Willis in one of his Die Hard movie to stop a bomb.

See Solution: How to measure 4 gallon water from 3 gallon and 5 gallon jar
There are 2 possible solutions i can think of

Solution 1:

  1. Fill 3 gallon jar with water.
  2. Pour all its water into 5 gallon jar.
  3. Fill 3 gallon jar again.
  4. Pour its water into 5 gallon jar untill it is full. Now you will have exactly 1 gallon water remaining in 3 gallon jar.
  5. Empty 5 gallon jar, pour 1 gallon water from 3 gallon jar into it. Now 5 gallon jar has exactly 1 gallon of water.
  6. Fill 3 gallon jar again and pour all its water into 5 gallon jar, thus 5 gallon jar will have exactly 4 gallon of water.

Solution 2:

  1. Fill 5 gallon jar.
  2. Pour all its water to 3 gallon jar, thus leaving exactly 2 gallon water in 5 gallon jar.
  3. Empty 3 gallon jar and pour all of 5 gallon jar water into it, thus now 3 gallon jar will have exactly 2 gallon of water.
  4. Fill 5 gallon jar again and pour its water to 3 gallon jar until that is full. So exactly 4 gallon water will remain in 5 gallon jar.

Four How many squares are there

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1.)

how many squares are in this picture

how many squares are in this picture

See Answer

There are total of 40 squares.

How?
Let’s assume the smallest square side is 0.5cm in length.

Now count the squares with different length :-
0.5cm : 8
1cm : 16 +2(in the middle)
2cm : 9
3cm : 4
4cm : 1
————
Total : 40

2.) How many squares are in this picture ?

how many squares

how many squares in this picture

See Answer
There are total of 16 squares.
How?

Lets count…
Squares with side length equal to 1 matchstick: 9
Squares with side length equal to 2 matchsticks: 5(2+1+2)
Square with side length equal to 3 matchsticks: 1 (This is difficult to find, and easy to miss)
Square with side length equal to 4 matchsticks: 1 (Everybody knows)
So total number of squares : 16

This image(courtsey Charles on facebook) explains it all:-

How many squares matchstick solution

How many squares matchstick solution

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Objective Questions set C/C++ – Part 5

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4 Objective type interview questions on C/C++ with answers

Before you start:-

  1. You can check your answer by filling a,b,c,d or e in the text box.
  2. You can get the answer by clicking Give Up Button.

Try yourself before giving up 🙂

Q1)

#include
int main(){
    char a[5]="hello";
    printf("%s",a);
}

Options: a) will print “hello” only b) will print some garbage values c) will print “hello” atleast d) None

Tried enough already?
[Read more…]

Objective Questions set C/C++ – Part 4

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10 Objective type interview questions with answers on C/C++

Before you start:-

  1. You can check your answer by filling a,b,c,d or e in the text box.
  2. You can get the answer by clicking Give Up Button.

Try yourself before giving up 🙂

Q1)

#include
main()
{
    unsigned char i;
    int sum=0;
    for(i=0;i<300;i++)
        sum=sum+i;
    printf("%d",sum);
}

Options: a) 44850 b) 45150 c) 300 d) Infinite Loop

Tried enough already?

Q2)

#include
fun(int i)
{
    int j=0;
    while (i & i-1) {
        j++;   
    }
    printf("%d",j);
}

main(){
    f(100);
}

Options: a. 100 b. 99 c. 2 d. 3

Tried enough already?

Q3)

Code 1 :
        for(i=0; i<1000; i++)
                for(j=0; j<100; j++)
                        x = y;

Code 2 :
        for(i=0; i<100; i++)
                for(j=0; j<1000; j++)
                        x = y;

Which code will execute faster ?
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Objective Questions set C/C++ – Part 3

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10 Objective type interview questions with answers on C/C++

Before you start:-

  1. You can check your answer by filling a,b,c,d or e in the text box.
  2. You can get the answer by clicking Give Up Button.

Try yourself before giving up 🙂

Q1) What will the below program prints ?

#include
void e( int );
main( )
{
    int a;
    a=3;
    e(a);
}

void e(int n)
{
    if (n>0)
    {
        e(--n);
        printf("%d",n);
        e(--n);
    }
}

Options: a) 0120 b) 0121 c) 0201 d) 0211

Tried enough already?
Q2)

#include
main( )
{
    int a[5]= {1,2,3,4,5};
    int*ptr = (int*)(&a+1);
    printf("%d %d", *(a+1), *(ptr-1));
}

Options: a)2 2 b) 2 1 c) 2 5 d) None

Tried enough already?
Q3)

#include
void foo(int [][3]);
main( )
{
    int a[3][3]={ {1,2,3}, {4,5,6}, {7,8,9} };
    foo(a);
    printf("%d", a[2][1]);
}

void foo(int b[][3])
{
    ++b;
    b[1][1]=35;
}

Options: a)8, b) 9, c) 7, d)35

Tried enough already?
Q4)
If performance is a critical requirement, then storage class should be used is ?
a)auto b) register c) extern d) static
Tried enough already?

Q5)
In a program
1-> char str1[ ] = “abc”;
2-> char *str2 = “xyz”;
3-> str2 = str1;
4-> str1 = str2;

Options:
a)compile error at line 3
b)compile error at line 4
c)no problem in the code
d)run time error

Tried enough already?

Q6)

int A = sizeof(char*)
int B = sizeof(int*)

a)A=B b)A<B c)A>B d) depends on compiler

Tried enough already?

Q7)

void func (int y)
{
static int x;
.
.
.
}

x and y will be stored on respectively in ?

Options:
a) stack and heap b) stack and data section c) data section and stack d) heap and data section

Tried enough already?

Q8)

#include

main(){
    int i=5;
    ++i++;
    printf("%d", i);
}

Options:
a)5 b) 6 c) 7 d) compilation error

Tried enough already?

Q9)
Statement 1-> const char *p1=”hello world”;
Statement 2-> char *const p2=”hello world”;
Statement 3-> p1=”welcome”;
Statement 4-> p2=”good bye”;
Statement 5-> *(p1+3) = ‘A’;
Statement 6­-> *(p2+3) = ‘A’;

Which statement cause problem ?

Options: a)4 & 5 b) 1 & 3 c) 3 & 5 d) 2 & 3

Tried enough already?

Q10)

#include
int function()
{
    static int a=0;
    a=a+1;
    return a;
}

main()
{
    function();
    function();
    printf("%d", function());
}

Options: a) 1 b) 2 c) 3 d) None

Tried enough already?

Objective Questions set C/C++ – Part 2

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10 Objective type interview questions with answers on C/C++

Before you start:-

  1. You can check your answer by filling a,b,c,d or e in the text box.
  2. You can get the answer by clicking Give Up Button.

Try yourself before giving up 🙂

Q1)

#include
struct XX{
    int a:10;
    int b:6;
    char c;
} structure;
int main(){
    int i = sizeof(structure);
    printf("%d", i);
}

Options: a) 4 b) 8 c) 9 d) 3 e) Compilation error

Tried enough already?

Q2)

#include
#include
main()
{
    char *s;
    s="hot java";
    strcpy(s,"solaris java");
    printf("%s", s);
}

Options:a) hot java b) solaris java c) compilation error d) Segmentation fault

Tried enough already?
[Read more…]

Objective Questions set C/C++ – Part 1

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10 Objective type interview questions with answers on C/C++

Before you start:-

  1. You can check your answer by filling a,b,c,d or e in the text box.
  2. You can get the answer by clicking Give Up Button.

Try yourself before giving up 🙂

Q1) What will be the output of the program below

#include
main(){
    int num[] = {1,4,8,12,16};
    int *p,*q;
    int i;
    p =  num;
    q = num+2;
    i = *p++;
    printf("%d, %d, %d\n",i, *p, *q);
}

Options a) 4, 4, 8 b) 1, 4, 8 c) 2, 1, 8 d) 2, 4, 8

Tried enough already?
Q2) What will be the output of the program below

#include

main(){
char *a[4]={"jaya","mahesh","chandra","swapant"};
int i = sizeof(a)/sizeof(char *);
printf("i = %d\n", i);
}

Options: a) 4 b) 7 c) 8 d) 1

Tried enough already?
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Puzzling Choices

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Are you making the right choice?

Tea or coffee? Walking or running? We are faced with so many lifestyle choices throughout the day, but how do you know you are making the right choice? Here is what experts say on Times of India article..

TEA OR COFFEE?

“Black tea usually has far less caffeine than coffee, while green tea is also packed with heart-healthy antioxidants.” says Kate Cook, nutrition coach. “Coffee acts a bit like rocket fuel, kick-starting adrenal glands and triggering the release of stress hormone, cortisol. Not the best start to the day.
Answer: Tea

FRUIT JUICE OR FRUIT?

“The fibre in fruits make it far more satisfying and filling with fewer calories.” says Kate. “Fruit juices have the fibre removed and tend to be loaded with sugar, which sends blood sugar level soaring — and then crushing.”
Answer: Fruit

EXERCISE IN THE MORNING OR EVENING?

“Studies shows that morning exercises are far more likely to stick with it,” explains Janey Holiday, fitness instructor: “You’re also likely to have a healthier day –from the food choices you make to how you feel mentally because of the endorphins flowing throughout your body. While exercise helps you sleep better; working out too late in the evening will actually disturb your sleep.”
Answer: Morning
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