c - 如何将字符串数组传递给 C 中的函数？

Question

所以我有这个函数 (makeStruct)，它能够接收一个字符串并打印出结构的元素。例如，我传入的字符串是 "a = 2.b, 1.d, 3.d; 4.o; milk cheese" 它通过存储每个数字的函数，字母和单词放入我创建的适当结构元素中。这工作得很好，但只有一个字符串:

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

struct stopPoints {
    int  weights[10];
    char connectingPoints[10];
    char *items[30];
    int startBool;
};


void makeStruct(char str[]){

    struct stopPoints myPoint;
    char *arr[30];
    char * pch;
    pch = strtok (str," ;=,.-");
    arr[0] = pch;
    int i=0;


  for (pch; pch != NULL; i++){
    pch = strtok (NULL, " ;=,.-");
    arr[i+1] = pch;
    //printf("%s\n", arr[i]);

  }
  printf("\n");
  char letters[10];
  int numbers[10];
  char *strings[10] = {NULL};
  int p, iter=0, iter2=0, iter3=0, val[10];
  for (p=0; arr[p] != NULL; p++){
      //if its a string
      if (isalpha(*arr[p]) && strlen(arr[p]) >=2 ){
        //printf("%s is a string\n", arr[p]);
        myPoint.items[iter] = arr[p];
        iter++;
      }
      //if its just a letter
      else if (isalpha(*arr[p]) && strlen(arr[p]) ==1){
        //printf("%s is a letter\n", arr[p]);
        letters[iter2] = *arr[p];
        myPoint.connectingPoints[iter2] = letters[iter2];
        iter2++;
        //printf("letter\n");
      }
      //if its a number
      else if (isdigit(*arr[p])){
        //printf("%s is a number\n", arr[p]);
        val[iter3] = atoi(arr[p]);
        myPoint.weights[iter3] = val [iter3];
        iter3++;
      }
  }



  printf("%s %s\n",  myPoint.items[0], myPoint.items[1]);

}


int main ()
{
        char str[] = "a = 2.b, 1.d, 3.d; 4.o; milk cheese";
        makeStruct(str);
  return 0;
}

现在，我希望能够将多个字符串传递给该函数。这就是我的问题所在。我尝试了几种不同的方法，但我不明白我哪里出错了。请看下面的代码:

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

struct stopPoints {
    int  weights[10];
    char connectingPoints[10];
    char *items[30];
    int startBool;
};


void makeStruct(char str[]){

    struct stopPoints myPoint;
    char *arr[30];
    char * pch;
    pch = strtok (str," ;=,.-");
    arr[0] = pch;
    int i=0;


  for (pch; pch != NULL; i++){
    pch = strtok (NULL, " ;=,.-");
    arr[i+1] = pch;
    //printf("%s\n", arr[i]);

  }
  printf("\n");
  char letters[10];
  int numbers[10];
  char *strings[10] = {NULL};
  int p, iter=0, iter2=0, iter3=0, val[10];
  for (p=0; arr[p] != NULL; p++){
      //if its a string
      if (isalpha(*arr[p]) && strlen(arr[p]) >=2 ){
        //printf("%s is a string\n", arr[p]);
        myPoint.items[iter] = arr[p];
        iter++;
      }
      //if its just a letter
      else if (isalpha(*arr[p]) && strlen(arr[p]) ==1){
        //printf("%s is a letter\n", arr[p]);
        letters[iter2] = *arr[p];
        myPoint.connectingPoints[iter2] = letters[iter2];
        iter2++;
        //printf("letter\n");
      }
      //if its a number
      else if (isdigit(*arr[p])){
        //printf("%s is a number\n", arr[p]);
        val[iter3] = atoi(arr[p]);
        myPoint.weights[iter3] = val [iter3];
        iter3++;
      }
  }



  printf("%s %s\n",  myPoint.items[0], myPoint.items[1]);

}


int main ()
{



    char *str[9];
    str[0] = "a = 2.b, 1.d, 3.d; 4.o; milk cheese";
    str[1] = "b = 2.a, 1.e, 2.c; water juice drinks";
    str[2] = "c = 2.b, 1.f; chips snacks";
    str[3] = "d = 1.a, 1.g; bread cereal pasta";
    str[4] = "e = 1.h, 1.b; meat chicken fish";
    str[5] = "f = 1.i, 1.c; oils sauces condiments";
    str[6] = "g = 1.j, 1.d; soup canned_goods";
    str[7] = "h = 1.k, 1.e; produce";
    str[8] = "i = 1.l, 1.f; beer";

    //char str[] = "a = 2.b, 1.d, 3.d; 4.o; milk cheese";

    int i;
    for (i=0; i<9; i++){
        makeStruct(*str);

    }

  return 0;
}

如您所见，我正在尝试接收 str[0]，输出我正在打印的语句，然后使用循环重复该过程以传入 str[1]、str[2]、str[3]、 等等等等。

那么现在，如何正确初始化包含多个字符串的数组，然后将这些字符串传递到我的 makeStruct 函数中？

Answer 1

当您在原始代码中执行此操作时:

char str[] = "a = 2.b, 1.d, 3.d; 4.o; milk cheese";

您正在创建一个 char 数组并使用给定字符串常量的内容对其进行初始化。这很好，因为即使无法更改字符串文字，str 也只包含该字符串文字内容的副本。

但是当你这样做的时候:

char *str[9];
str[0] = "a = 2.b, 1.d, 3.d; 4.o; milk cheese";
str[1] = "b = 2.a, 1.e, 2.c; water juice drinks";
...

您正在创建一个指针 数组，并为每个指针分配一个字符串文字的地址。因此，当您将 *str 传递给您的函数时，它会尝试通过 strtok 函数修改字符串文字，这是不允许的。

您应该创建一个 char 的二维数组，并用字符串常量初始化:

char str[9][50] = {
    "a = 2.b, 1.d, 3.d; 4.o; milk cheese",
    "b = 2.a, 1.e, 2.c; water juice drinks",
    "c = 2.b, 1.f; chips snacks",
    "d = 1.a, 1.g; bread cereal pasta",
    "e = 1.h, 1.b; meat chicken fish",
    "f = 1.i, 1.c; oils sauces condiments",
    "g = 1.j, 1.d; soup canned_goods",
    "h = 1.k, 1.e; produce",
    "i = 1.l, 1.f; beer"
};

此外，您的循环始终发送数组的第一个元素:

for (i=0; i<9; i++){
    makeStruct(*str);
}

索引数组以传入连续元素:

for (i=0; i<9; i++){
    makeStruct(str[i]);
}