我在从一个单独的函数中编辑一个结构的字段时遇到了问题，我试图从update droneinfofunction中编辑我的无人机结构的字段，基本上我的所有箭头都得到了同样的错误（无效类型参数'->'）。
我确信这个问题源于我对指针的不理解。
任何帮助将是非常感激:)
这里是代码。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define DRONE_COUNT 10
typedef struct{
//define struct info and variables
int drone_number;
char drone_name[20];
int year_manufactured;
double mass;
double top_speed;
double max_distance;
double load_capacity;
} drone_info;
int updateDroneInfo(drone_info *droneinfo, int no_of_drones) {
int searchID, numdrones, i, drYrMan;
double drMass, drTopSpeed, drMaxDist, drLoadCap;
char drname[20];
numdrones = no_of_drones;
printf("what drone ID would you like to update?: ");
scanf("%d", &searchID);
printf("name: ");
scanf("%s", drname);
printf("year manufactured: ");
scanf("%d", &drYrMan);
printf("mass: ");
scanf("%lf", &drMass);
printf("top speed: ");
scanf("%lf", &drTopSpeed);
printf("max distance: ");
scanf("%lf", &drMaxDist);
printf("load capacity: ");
scanf("%lf", &drLoadCap);
droneinfo[searchID]->drone_number = searchID;
droneinfo[searchID]->drone_name = drname;
droneinfo[searchID]->year_manufactured = drYrMan;
droneinfo[searchID]->mass = drMass;
droneinfo[searchID]->top_speed = drTopSpeed;
droneinfo[searchID]->max_distance = drMaxDist;
droneinfo[searchID]->load_capacity = drLoadCap;
for(i=0; i < numdrones; i++){
}
return 0;
}
//drone search function
int searchDroneName(drone_info *droneinfo, int no_of_drones){
int i, found;
char namechoice[20];
printf("input drone name: ");
scanf("%s", namechoice);
found=0;
scanf("what drone would you like to search %s", namechoice);
for (i=0; i < no_of_drones; i++){
if (!strcmp(namechoice, droneinfo[i].drone_name)) {
printf("found a match\n\nID: %d Name: %s Year: %d Mass: %.2f Top Speed: %.2f Max Distance: %.2f Load Capacity: %.2f\n",
droneinfo[i].drone_number, droneinfo[i].drone_name, droneinfo[i].year_manufactured, droneinfo[i].mass, droneinfo[i].top_speed, droneinfo[i].max_distance, droneinfo[i].load_capacity);
found = 1;
}
}
if(found == 0){
printf("\nNo matches were found!\n");
}
return 0;
//make condition for all
}
int main(void) {
drone_info droneinfo[10];
int choice, droneID, yrman, i, no_of_drones;
double dronemass, dronemaxdist, dronetopspd, droneload;
char dronename[20];
i=0;
//open the drone.txt file where the drone info is stored
FILE* inputfile = fopen("drone.txt", "r");
if(inputfile == NULL)
{
perror("ERROR! ");
exit(-1);
}
//initialise the function that puts the struct in an array
while(fscanf(inputfile, "%d %19s %d %lf %lf %lf %lf", &droneID, dronename, &yrman, &dronemass, &dronetopspd, &dronemaxdist, &droneload)==7){
if(ferror(inputfile)){
perror("An error occurred: ");
}
droneinfo[i].drone_number = droneID;
strcpy(droneinfo[i].drone_name, dronename);
droneinfo[i].year_manufactured = yrman;
droneinfo[i].mass = dronemass;
droneinfo[i].top_speed = dronetopspd;
droneinfo[i].max_distance = dronemaxdist;
droneinfo[i].load_capacity = droneload;
i++;
}
no_of_drones = i;
fclose(inputfile);
//print the dtone info in an array
printf("Data:\n\n");
for (i=0; i < no_of_drones; i++){
printf("ID: %d Name: %s Year: %d Mass: %.2f Top Speed: %.2f Max Distance: %.2f Load Capacity: %.2f\n",
droneinfo[i].drone_number, droneinfo[i].drone_name, droneinfo[i].year_manufactured, droneinfo[i].mass, droneinfo[i].top_speed, droneinfo[i].max_distance, droneinfo[i].load_capacity);
}
do{
//program menu with appropriate menu items
printf("Please select an option:\n\n");
printf("1. Input/update drone information\n");
printf("2. Search a drone\n");
printf("3. Simulate a drone delivery scenario\n");
printf("4. Display simulation results\n");
printf("5. Save drone information\n");
printf("6. Save all results\n");
printf("7. Exit\n\n");
scanf("%d", &choice);
//switch for the 7 available menu cases
switch(choice)
{
case 1:
//input drone function
updateDroneInfo(droneinfo, no_of_drones);
break;
case 2:
//search drone function
searchDroneName(droneinfo, no_of_drones);
break;
case 3:
//simulate drone function
break;
case 4:
//display simulation results
break;
case 5:
//save drone information
break;
case 6:
//save all results function
break;
case 7:
//exit/breaks the loop
break;
default:
printf("Invalid Data Entered! please enter a number between 1 and 7\n\n");
break;
}
} while(choice != 7);
return 0;
}
re
droneinfo[searchID]
类型为 drone_info 而不是 drone_info*，所以你用 . 而不是 ->.
在这样的陈述中
droneinfo[searchID]->drone_number = searchID;
语气 droneinfo[searchID] 不是一个指针。它的类型是 drone_info 因为指针 droneinfo 已经被下标操作符取消了引用。
您必须写下
droneinfo[searchID].drone_number = searchID;
另外数组没有赋值操作符。你需要将元素元素从一个数组复制到另一个数组。
我们可以用以下语句来代替
droneinfo[searchID]->drone_name = drname;
你必须使用标准的字符串函数来写。strcpy
$include <string.h>
//...
strcpy( droneinfo[searchID].drone_name, drname );