C Code for cryptographic algorithm

[Dinal]

i have a problem... i have to seperate numbers from digits. For example i have a cryptographic code done which gives me the output as
2_three_06_one_ 01_four_32_two_ 3
I need to seperate the numbers and print them like it should be 2 6 13 23

[weaknessforcats]

Can't you just read your input a byte at a time and check whether the byte value is between 49 and 57 on the ascii table.? or pass your byte to isdigit()?

[jaseel97]

char rawdata[]="2_three_01_si x"
int i = 0
while i<rawdata.lengt h()
{
if string.isdigit( rawdata[i]) && rawdata[i-1]!='_'
print rawdata[i]
i=i+1
}
Will this work?? @weaknessforcat s

[donbock]

@jaseel97 you need to print some separator (space, new line, etc) between numbers.

[weaknessforcats]

@jaseel97:
It worked for me. Of course, I had to fix the code errors but the logic flow is correct.

[Sherin]

Try This code

#include<iostream>
#include<math.h>
using namespace std;
// find gcd
int gcd(int a, int b) {
   int t;
   while(1) {
      t= a%b;
      if(t==0)
      return b;
      a = b;
      b= t;
   }
}
int main() {
   //2 random prime numbers
   double p = 13;
   double q = 11;
   double n=p*q;//calculate n
   double track;
   double phi= (p-1)*(q-1);//calculate phi
   //public key
   //e stands for encrypt
   double e=7;
   //for checking that 1 < e < phi(n) and gcd(e, phi(n)) = 1; i.e., e and phi(n) are coprime.
   while(e<phi) {
      track = gcd(e,phi);
      if(track==1)
         break;
      else
         e++;
   }
   //private key
   //d stands for decrypt
   //choosing d such that it satisfies d*e = 1 mod phi
   double d1=1/e;
   double d=fmod(d1,phi);
   double message = 9;
   double c = pow(message,e); //encrypt the message
   double m = pow(c,d);
   c=fmod(c,n);
   m=fmod(m,n);
   cout<<"Original Message = "<<message;
   cout<<"\n"<<"p = "<<p;
   cout<<"\n"<<"q = "<<q;
   cout<<"\n"<<"n = pq = "<<n;
   cout<<"\n"<<"phi = "<<phi;
   cout<<"\n"<<"e = "<<e;
   cout<<"\n"<<"d = "<<d;
   cout<<"\n"<<"Encrypted message = "<<c;
   cout<<"\n"<<"Decrypted message = "<<m;
   return 0;
}

Output

p = 13
q = 11
n = pq = 143
phi = 120
e = 7
d = 0.142857
Original Message = 9

Encrypted message = 48
Decrypted message = 9

[SwissProgrammer]

In case the reader is new to programming the following is a process that has been used for many years.

For C++, if your input is a std::string, or if you convert your input into a std::string, then parse it for what you want. Use the result of your parsing.

Study std::string, and parsing, and go from there.