#include <stdio.h>
#include <cs50.h>
#include <string.h>
#include <ctype.h>
int main (int argc, string argv[]){
///turn command line string into int///
int s = (atoi(argv[1]))%26;
//return error message for no command line arg///
if (argc!=2) {
printf("Error: No command line argument\n");
return 1;
}
//prompt user for plaintext//
printf("plaintext: ");
string p = get_string();
//print loop for ciphertext//
printf("ciphertext: ");
int n = strlen(p);
for (int i=0; i<n; i++) {
//if char is alphabetical inner loops preserve case//
if (isalpha(p[i])) {
if (isupper(p[i])) {
char l = p[i]+ s;
if (l>=90) {
l = s + 65;
}
printf("%c", l);
}
if (islower(p[i])) {
char m = p[i] + s;
if (m>=122) {
m = s + 97;
}
printf("%c", m);
}
}
///if not a letter, prints as is//
if (isalpha(p[i]) == false) {
printf("%c", p[i]);
}
}
///print new line after ciphertext///
printf("\n");
return 0;
}
:) caesar.c exists.
:) caesar.c compiles.
:) encrypts "a" as "b" using 1 as key
:( encrypts "barfoo" as "yxocll" using 23 as key
output not valid ASCII text
:) encrypts "BARFOO" as "EDUIRR" using 3 as key
:) encrypts "BaRFoo" as "FeVJss" using 4 as key
:( encrypts "barfoo" as "onesbb" using 65 as key
expected "ciphertext: one...", not "ciphertext: onn..."
:( handles lack of argv[1]
failed to execute program due to segmentation fault
Anonymous - 2 years ago