CODEWITHSUNDEEP
carraysstringfor-loopprinting
Defcon97
Defcon97

Reputation: 121

Issue with string printing

I was trying to create a program to ecrypt string with Ceasar's cypher, if you are not familiar with the Ceasar cypher it is a really simple encryption method, it operates using the input string and a number "n" that can be chosen by the user and then just shifts the whole alphabet n-times. for axample if n=1 then all the A's become B's and so on. this program should have an input string that should be read by the program via keyboard input and an n number that has to be chosen by the user as well; and should return a string where the first character represents the first character uf the unencrypted string and then the following characters should be the encypted version of the input string, encrypted with Ceasar's cypher using the n number chosen by the user. for the sake of brevity I have not included in this post the part of the code where the program scans the n value and adjusts it (it obviously has to be smaller than 26), and I have canceled as well the part of the program that turned the input string in upper case.

int main() {
  int i, n;
  char uncod[200] = {0};
  char cod[200] = {0};
  printf("insert the string to encript:");
  scanf("%[0-9a-zA-ZSPACE]", uncod);
    cod[0] = (char)uncod[0];
    for(i == 1; i < 200; i++) {
      sprintf(cod, "%d + n", uncod[i]);
      if (cod[i] > 90) {
    cod[i] = 64 + n;
      }
      if (cod[i] < 65) {
    cod[i] = 91 + n;
    }
    };
     printf("%s\n", cod);
}

This program should take the ASCII code of the unencypted string and add or subtract n to find te right character by mere assignation, it just runs through the array and assigns to every character his cyphered counter-part after having assigned to the first value of the output string the unencrypted first character of the input string. The issue is that when I go to print the output string, it'll only print the first character and ignore the rest. how to solve this?

Upvotes: 0

Views: 73

Answers (2)

Mike
Mike

Reputation: 167

You should know that String contains only characters and after adding some value in the character value, their ASCII code will be different For an example: if you will add 50 in the ASCII code of ‘A’ it will be 65+50 = 135 and the character will be different and some time value exceeds the maximum limit of char that is 128. And string will not print because string is converted into BYTE buffer; what you have to do? Use unsigned char instead of char [limit will be 0-255] and you can it is byte buffer And print the values of the byte buffer in either integer using %d or in hexadecimal using %02X. *Here is the code snippet to print the BYTE buffer in Hexadecimal *

for(loop=0; loop<5; loop++)
{
    printf("hexV[%d] : %02X\n",loop,hexV[loop]);
}

Reference taken from: C program to assign and copy hexadecimal values in character buffer.

Upvotes: 0

eyalm
eyalm

Reputation: 3366

  • n is not initialized anywhere.
  • Not sure what this line is supposed to do "sprintf(cod, "%d + n", uncod[i])". Why concatenating such a string to your encrypted output?
  • You would probably want to stop the loop when string is terminated (\0).

Upvotes: 1

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