Question

我对C语法有点问题。我想构建一个struct数组。但它返回

预期的声明说明符或'city'之前的'...'

这是我的代码

    #include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>

struct City {
  int plateNumber;
  char name[32];
  double area;
  int population;
  int populationDensity;
  int cityCenterPopulation;
  char region[32];
  double latitude;
  double longitude;
};

struct City cities[81];
#define Struct_Size sizeof(struct City)

void printCityData(cities[], int i);
void readFile();

void readFile(){
  int fd = open("data.dat", O_RDONLY);
  if(fd<0) {
    printf("Error while opening file!");
    return;
  }
  int i;
  for (i = 0; i < 81; i++) {
    while(read(fd,&cities[i], Struct_Size)>0) {
      printCityData(cities[i],i);
    }
  }

}

void printCityData(cities[], int i) {
  printf("CITIES\n");
  printf("plateNumber: %d\n", cities[i].plateNumber);
  printf("name: %s\n", cities[i].name);
  printf("area: %lf\n", cities[i].area);
  printf("population: %d\n", cities[i].population);
  printf("populationDensity: %d\n", cities[i].populationDensity);
  printf("cityCenterPopulation: %d\n", cities[i].cityCenterPopulation);
  printf("region: %s\n", cities[i].region);
  printf("latitude: %lf\n", cities[i].latitude);
  printf("longitude: %lf\n", cities[i].longitude);
}

int main(int argc, char const *argv[]) {
  readFile();
  return 0;
}

我该如何解决这个问题？

Answer 1

我相信，问题是由于

中的cities[]之前缺少数据类型

 void printCityData(cities[], int i)

应该是

 void printCityData(struct City cities[], int i)

请记住，cities是变量，而不是数据类型。 FWIW，在前向声明的情况下，您实际上可以省略变量名称而不是变量类型。

那就是说，实际上，cities在这里是全局变量，你不需要将它作为参数传递。您可以将功能签名缩小为

void printCityData(int i) {

并将其称为

 printCityData(i);

Answer 2

问题是你没有提到城市的数据类型，而且你正在使用与我想象的不同的数据类型调用该函数。我做了所需的更改：

#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>

struct City {
  int plateNumber;
  char name[32];
  double area;
  int population;
  int populationDensity;
  int cityCenterPopulation;
  char region[32];
  double latitude;
  double longitude;
};

struct City cities[81];
#define Struct_Size sizeof(struct City)

void printCityData(struct City cities[], int i); //cities is an array of struct City
void readFile();

void readFile(){
  int fd = open("data.dat", O_RDONLY);
  if(fd<0) {
    printf("Error while opening file!");
    return;
  }
  int i;
  for (i = 0; i < 81; i++) {
    while(read(fd,&cities[i], Struct_Size)>0) {
      printCityData(cities,i);
    }
  }

}

void printCityData(struct City cities[], int i) {
  printf("CITIES\n");
  printf("plateNumber: %d\n", cities[i].plateNumber);
  printf("name: %s\n", cities[i].name);
  printf("area: %lf\n", cities[i].area);
  printf("population: %d\n", cities[i].population);
  printf("populationDensity: %d\n", cities[i].populationDensity);
  printf("cityCenterPopulation: %d\n", cities[i].cityCenterPopulation);
  printf("region: %s\n", cities[i].region);
  printf("latitude: %lf\n", cities[i].latitude);
  printf("longitude: %lf\n", cities[i].longitude);
}

int main(int argc, char const *argv[]) {
  readFile();
  return 0;
}

C结构声明

2 个答案: