I know that this question have been asked before, but I still can't find the clue to the problem in my code. My program works apparently fine, but I'm not able to pass the check50 test. From what I understand, the issue may be related to the fact that the null \0 is printed. But I don't know how to modify that. Could you please help me?
This is my code:
#include <cs50.h>
#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
bool only_digits(string s);
char rotate(char c, int n);
int main(int argc, string argv[])
{
string h = argv[1];
if (argc != 2 || !only_digits(h) || h <= 0)
{printf("Usage: ./caesar key\n");
return 1;
}
else
{
int key = atoi(argv[1]);
string plaintext = get_string("plaintext: ");
int f = strlen(plaintext);
printf("ciphertext: ");
for(int q = 0; q < f; q++)
{
printf("%c", rotate(plaintext[q], key));
}
printf("\n");
}
return 0;
}
bool only_digits(string s )
{
for (int i = 0, n = strlen(s); i < n; i++)
{
char digit = s[i];
if (!isdigit(digit))
return false;
}
return true;
}
char rotate(char c, int n)
{
if(isupper(c) && (c != '\0'))
{
printf("%c", (((c - 65) + n) % 26) + 65);
}
else
if(islower(c) && (c != '\0'))
{
printf("%c", (((c - 97) + n) % 26) + 97);
}
else
printf("%c", c);
return 0;
}
This is a caption of check50's check: check50
rotate
always returns 0
, so printf("%c", rotate(plaintext[q], key));
is causing the letters you output to be interspaced with NUL characters.
I would keep that printf
, but change rotate
to return the character instead of printing it.
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