[英]2D character array contents getting overwritten
I am trying to read a string and reverse the words in the string., but the content of the strings is getting overwritten and I am getting garbage values for the first few strings in the 2D array. 我试图读取一个字符串并反转该字符串中的单词。但是,字符串的内容被覆盖,并且我正在获取2D数组中前几个字符串的垃圾值。 Eg when I print the words in reverse order at the end of the function, I am getting junk for the first few strings.
例如,当我在函数末尾以相反顺序打印单词时,前几个字符串会变得很乱。 What am I doing wrong?
我究竟做错了什么?
void reverseWords(char *s) {
char** words;
int word_count = 0;
/*Create an array of all the words that appear in the string*/
const char *delim = " ";
char *token;
token = strtok(s, delim);
while(token != NULL){
word_count++;
words = realloc(words, word_count * sizeof(char));
if(words == NULL){
printf("malloc failed\n");
exit(0);
}
words[word_count - 1] = strdup(token);
token = strtok(NULL, delim);
}
/*Traverse the list backwards and check the words*/
int count = word_count;
while(count > 0){
printf("%d %s\n",count - 1, words[count - 1]);
count--;
}
}
You need to change that line: 您需要更改该行:
words = realloc(words, word_count * sizeof(char));
You allocate char
s, that is, single characters. 您分配
char
,即单个字符。 You want pointers. 您需要指针。 Therefore, use this:
因此,使用此:
words = realloc(words, word_count * sizeof(char*));
Also, as @ Snild Dolkow stated, initialize words
to NULL
. 同样,如@ Snild Dolkow所述,将
words
初始化为NULL
。 Otherwise realloc
will attempt to use the undefined value of words
as the memory to reallocate. 否则,
realloc
将尝试使用未定义的words
值作为要重新分配的内存。 Further information at man realloc
. 有关更多信息,请
man realloc
。
Notes: 笔记:
free
the memory returned to you by strdup
after usage free
strdup
返回给您的内存
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