Question

我需要编写一个C函数，它从用户那里获取他想要输入的单词的数量，然后该函数必须从用户扫描单词，但是在数组中扫描它们。

例如：

程序：

number of words:

用户：

3
hi
my
name

（在每个单词之间有输入）然后该函数必须将这些单词放入字符串数组（数组的大小必须由malloc定义，字符串的最大大小为100（可能更小））。

int main()
{
    int n;
    printf("Please enter the number of words: \n");
    if (scanf("%d",&n)!=1) 
        return 0;
    char *name;
    name = malloc((sizeof(char)*100*n));
    int c;
    int i;
    int m;
    for (i = 0; i < n && ((c=getchar()) != EOF );i++)
    {
        name[i] = c;
    }
    finds_themin(&name, m); //I know this work
    return 0;
}

Answer 1

当你需要存储一个字符串数组时，需要一个char*或char**数组来指向每个字符串（char数组）。

char **name;
name = malloc(n); // to store n strings.

然后在循环中使用fgets将输入读作一行。此外，您需要为每个新的char数组分配内存。

fflush(stdin);
for (i = 0; i < n; i++) {
    name[i] = malloc(100); // allocating memory for string.
    fgets (name[i], 100, stdin); // 100 is the max len
}

然后，您可以简单地遍历char**数组，i索引将指向i字符串。

for (i = 0; i < n; i++) {
    // printf("%s", name[i]);
}

Answer 2

您需要设置指针指针。

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

int main(){

    char **s;
    int n;
    char buffer[64];
    fgets(buffer,64,stdin);
    n=strtol(buffer,NULL,10);// I avoid using scanf

    s=(char **)malloc(sizeof(char*)*n);// you need to declare a pointer to pointer

    /*
        'PtP s' would look like this:
      s[0]=a char pointer so this will point to an individual string
      s[1]=a char pointer so this will point to an individual string
      s[2]=a char pointer so this will point to an individual string
         ....

      so you need to allocate memory for each pointer within s.
    */
    int i;
    for(i=0;i<n;i++){
        s[i]=(char*)malloc(sizeof(char)*100);// length of each string is 100 in this case
    }

    for(i=0;i<n;i++){

        fgets(s[i],100,stdin);

        if(strlen(s[i])>=1){// to avoid undefined behavior in case of null byte input
            if(s[i][strlen(s[i])-1]=='\n'){ // fgets also puts that newline character if the string is smaller than from max length,

                s[i][strlen(s[i])-1]='\0'; // just removing that newline feed from each string
            }

           else{

               while((getchar())!='\n'); //if the string in the command line was more than 100 chars you need to remove the remaining chars for next fgets
           }
         }
   }

    for(i=0;i<n;i++){
        printf("\n%s",s[i]);
    }
    for(i=0;i<n;i++){
        free(s[i]); //avoiding leaks
    }
    free(s);
}

函数获取单词并将它们放在数组

2 个答案: