[英]CS50 Vigenere - Output Incorrect
男人,我以為我有它! 我一直在研究Vigenere問題,並且已經很接近了,但是當我檢查時一直收到此錯誤。 密鑰必須環回時似乎存在問題。 有什么想法嗎?
這是錯誤:
:) vigenere.c exists
:) vigenere.c compiles
:) encrypts "a" as "a" using "a" as keyword :( encrypts "world, say hello!" as "xoqmd, rby gflkp!" using "baz" as keyword \ expected output, but not "xoqmj, yfz gflkp!\n"
:( encrypts "BaRFoo" as "CaQGon" using "BaZ" as keyword \ expected output, but not "CaQAun\n"
:( encrypts "BARFOO" as "CAQGON" using "BAZ" as keyword \ expected output, but not "CAQAON\n"
:) handles lack of argv[1]
:) handles argc > 2
:) rejects "Hax0r2" as keyword
這是我的代碼:
#include <stdio.h>
#include <cs50.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#define FALSE 0
#define TRUE 1
int main(int argc, string argv[])
{
string key = argv[1];
if (argc!= 2)
{
printf("please provide only one perameter \n");
// stop the program
return 1;
}
// iterate over the key to make sure its all alpha
int i,j;
for (i = 0, j = strlen(key); i < j; i++)
{
if (!isalpha(key[i]))
{
printf("please use only alphanumeric values \n");
return 1;
}
}
// now we have a key, "key" from the ONE perameter that is all alpha
string message = GetString();
int k = 0;
int keyindex;
for (i = 0, j = strlen(message); i < j; i++, k++)
{
if (isalpha(message[i]))
{
keyindex = k % strlen(argv[1]);
// covering the upper case letters
if (isupper(message[i]))
{
// covering the upper case letters with upper case key letters
if isupper(key[i])
{
// print cipher according to two upper case
int cipher = ((message[i] - 65 + key[keyindex] - 65) % 26)
+ 65;
printf("%c", cipher);
}
else
{
// print according to upper case message lower case key
int cipher = ((message[i] - 65 + key[keyindex] - 97) % 26)
+ 65;
printf("%c", cipher);
}
}
// this is for the non upper case letters
if (islower(message[i]))
{
if isupper(key[i])
{
// print cipher according to lower case message and
// upper case key letter
int cipher = ((message[i] - 97 + key[keyindex] - 65) % 26)
+ 97;
printf("%c", cipher);
}
else
{
// print according to lower case message and lower case key
int cipher = ((message[i] - 97 + key[keyindex] - 97) % 26)
+ 97;
printf("%c", cipher);
}
}
}
// non alpha symbols
else
{
printf("%c", message[i]);
}
}
// end program after iterating
printf("\n");
}
您的程序存在問題:
1)Sytax錯誤,應避免對其進行編譯:
if isupper(key[i])
-> if (isupper(key[i]))
其中有兩個,因此請確保將它們都修復。
2)遞增k
int k = 0;
...
for (i = 0, j = strlen(message); i < j; i++, k++)
{
if (isalpha(message[i]))
{
keyindex = k % strlen(argv[1]);
有兩種方法可以解決這個問題,要么在每個字符上增加k
,要么在每個字母上增加k
。 這個問題的設計者選擇了letter,因此我們需要做的是:
int k = 0;
...
for (i = 0, j = strlen(message); i < j; i++)
{
if (isalpha(message[i]))
{
keyindex = k++ % strlen(argv[1]);
3)現在我們已經定義了keyindex
:
if isupper(key[i])
-> if isupper(key[keyindex])
其中有兩個,因此請確保將它們都修復。
應用這些更改和一點樣式清除,我們得到:
#include <stdio.h>
#include <cs50.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
int main(int argc, string argv[])
{
if (argc != 2)
{
printf("please provide only one parameter \n");
return 1; // stop the program
}
string key = argv[1];
// iterate over the key to make sure it's all alpha
for (int i = 0, j = strlen(key); i < j; i++)
{
if (!isalpha(key[i]))
{
printf("please use only alphanumeric values \n");
return 1;
}
}
// now we have a key, "key" from the ONE parameter that is all alpha
string message = GetString();
for (int i = 0, k = 0, j = strlen(message); i < j; i++)
{
if (isalpha(message[i]))
{
int keyindex = k++ % strlen(key);
if (isupper(message[i])) // covering the upper case letters
{
if (isupper(key[keyindex]))
{
// print cipher according to both upper case
int cipher = ((message[i] - 'A' + key[keyindex] - 'A') % 26) + 'A';
printf("%c", cipher);
}
else
{
// print cipher according to upper case message and lower case key
int cipher = ((message[i] - 'A' + key[keyindex] - 'a') % 26) + 'A';
printf("%c", cipher);
}
}
else // this is for the non upper case letters
{
if (isupper(key[keyindex]))
{
// print cipher according to lower case message and upper case key letter
int cipher = ((message[i] - 'a' + key[keyindex] - 'A') % 26) + 'a';
printf("%c", cipher);
}
else
{
// print cipher according to both lower case
int cipher = ((message[i] - 'a' + key[keyindex] - 'a') % 26) + 'a';
printf("%c", cipher);
}
}
}
else // non alpha symbols
{
printf("%c", message[i]);
}
}
printf("\n"); // end program after iterating
}
您的代碼重復了很多邏輯,可以將這些邏輯與較小的更改結合在一起-重復的邏輯是一種難以發現錯誤的錯誤代碼。
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