### Birthday problem

How many people must be there in a room to make the probability 100% that two people in the room have same birthday?

Answer: 367 (since there are 366 possible birthdays, including February 29).
The above question was simple. Try the below question yourself.

How many people must be there in a room to make the probability 50% that two people in the room have same birthday?

The number is surprisingly very low. In fact, we need only 70 people to make the probability 99.9 %.

np(n)
10.0%
52.7%
1011.7%
2041.1%
2350.7%
3070.6%
4089.1%
5097.0%
6099.4%
7099.9%
10099.99997%
20099.9999999999999999999999999998%
300(100 − (6×10−80))%
350(100 − (3×10−129))%
365(100 − (1.45×10−155))%
366100%
367100%

$n(p;d)\approx \sqrt{2d \cdot \ln\left({1 \over 1-p}\right)}.$

// Returns approximate number of people for a given probability
int find(double p)
{
    return ceil(sqrt(2*365*log(1/(1-p))));
}

### C Questions

C Questions
C Questions

Note : All the programs are tested under Turbo C/C++ compilers.
It is assumed that,
Programs run under DOS environment, The underlying machine is an x86 system, Program is compiled using Turbo C/C++ compiler.
The program output may depend on the information based on this assumptions (for example sizeof(int) == 2 may be assumed).
Predict the output or error(s) for the following:

void main()
{
int const * p=5; printf("%d",++(*p));
}
Compiler error: Cannot modify a constant value.
Explanation:
p is a pointer to a "constant integer". But we tried to change the value of the "constant integer".
main()
{
char s[ ]="man"; int i;
for(i=0;s[ i ];i++)
printf("\n%c%c%c%c",s[ i ],*(s+i),*(i+s),i[s]);
}
aaaa nnnn
Explanation

### Zoho Interview | Set 1 (Advanced Programming Round)

Third Round: (Advanced Programming Round) Here they asked us to create a “Railway reservation system” and gave us 4 modules. The modules were:
1. Booking
2. Availability checking
3. Cancellation
4. Prepare chart
We were asked to create the modules for representing each data first and to continue with the implementation phase.

My Solution :