free():无效的指针异常终止(核心已转储)cs50 [英] free(): invalid pointer Aborted (core dumped) cs50
问题描述
我在替换密码方面遇到问题,我无法正确确定我的代码功能,但是在我的密文末尾会打印出额外的感叹号,这是代码的重要部分
I'm having problem with substitution cipher that I can't figure out my code functions correctly but it prints extra exclamation mark at the end of my ciphertext here is my important part of the code
int keylen = strlen(argv[1]);
string key = argv[1];
printf("ciphertext: ");
for (int i = 0; i < keylen; i++)
{
//if it is a lower character we remove the value of a
//to make it the letters start form 0
if (islower(plaintext[i]))
{
int x = plaintext[i] - 'a';
printf("%c", tolower(key[x]));
}
// the same goes here for uppercase
else if (isupper(plaintext[i]))
{
int y = plaintext[i] - 'A';
printf("%c", toupper(key[y]));
}
else
{
//if the text is not an alphabet letter print it as it is
printf("%c", plaintext[i]);
}
}
这是输出 〜/pset2/substitution/$ ./subs JTREKYAVOGDXPSNCUIZLFBMWHQ
This is the output ~/pset2/substitution/ $ ./subs JTREKYAVOGDXPSNCUIZLFBMWHQ
纯文本:您好
密文:vkxxn!
然后,我尝试在if语句之后的循环中将其添加为大写形式,如下所示:
Then I tried adding this in the loop after the if statement that checks for uppercase like so:
else if (isupper(plaintext[i]))
{
int y = plaintext[i] - 'A';
printf("%c", toupper(key[y]));
}
// breaks at \0 to prevent printing garbage values
else if (plaintext[i] = '\0')
{
break;
}
我得到这个奇怪的错误 〜/pset2/substitution/$ ./subs JTREKYAVOGDXPSNCUIZLFBMWHQ
and I get this weird error ~/pset2/substitution/ $ ./subs JTREKYAVOGDXPSNCUIZLFBMWHQ
纯文本:您好
密文:vkxxn
free():无效的指针
free(): invalid pointer
已中止(核心已弃用)
对于这个冗长的问题,我深表歉意,谢谢大家的宝贵时间.
I apologize for this lengthy question and thank you all for your time.
推荐答案
我找到了导致错误的代码
I found the code that makes the error
else if (plaintext[i] = '\0')
{
break;
}
在这里,我将值分配给'\ 0'而不是通过双等号==
检查该值
Here I'm assigning the value to '\0' instead of checking the value by double equal signs ==
that what gives that error
free():无效的指针
中止(核心已弃用)
free(): invalid pointer
Aborted (core dumped)
再次感谢您的时间
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