在存储数据时，结构存在问题。我想做一个哨点循环，所以请看一下并帮助我，谢谢。
#include<stdio.h>
#include<stdlib.h>
struct Vehichle
{
char vecType[100];
char plateNo[10];
float hours;
};
struct Parking
{
int parkNo ;
// 1 =true 0=false
int availability;
};
int main()
{
int c = 0;
int x;
struct Vehichle vehicle[c];
struct Parking park[50];
int counter = 1;
while(x!=-1)
{
printf("Enter -1 to end: \n");
scanf("%d", &x);
printf("Enter Vehicle Type etc: suv,mpv and more:");
scanf("%d",&vehicle[x].vecType);
printf("Please enter parking Number :");
scanf("%d",&park[x].parkNo);
park[x].availability = 1;
counter++;
}
}
我希望将其存储在结构中之后，程序将循环运行。
答案 0 :(得分：2)
您的代码中存在许多问题。这是您在我的代码中添加了一些注释的代码：
int main()
{
int c = 0;
int x; // UPS: x is uninitialized
struct Vehichle vehicle[c]; // UPS: c is zero so you don't get an array
struct Parking park[50];
int counter = 1;
while(x!=-1) // UPS: Use of uninitialized x
{
printf("Enter -1 to end: \n");
scanf("%d", &x);
printf("Enter Vehicle Type etc: suv,mpv and more:");
scanf("%d",&vehicle[x].vecType); // UPS: vecType is char array so
// use %s instead of %d
// and don't use a &
printf("Please enter parking Number :");
scanf("%d",&park[x].parkNo);
park[x].availability = 1;
counter++;
}
}
当用户输入为-1时，您还有问题。当前代码只是继续，并在索引-1处添加了一个元素。那是非法的。
要解决此问题，请在scanf之后添加一行。喜欢：
scanf("%d", &x);
if (x == -1) break; // Stop the while loop
通过此更改，您可以执行while(1)而不是while(x!=-1)
一些额外的评论：
您应检查用户输入（aka x）是否在有效范围内以用作数组索引。
您还应该检查scanf的返回值。喜欢：
if (scanf("%d", &x) != 1)
{
// Invalid input"
... error handling ...
}
答案 1 :(得分：0)
（1）由于您的代码有几个问题，因此下面是更新的代码。 我敢肯定，查看下面的代码，您将能够理解代码中的错误。 随意将其用作编写自己的版本的基础。 （2）请仔细阅读内联注释。精心评论 解释该部分代码的意图 （3）这只是一个快速代码。我尚未编译/运行/测试此代码。 我的目的只是通过一个可能的示例为您提供一个想法。
/ *一个非常基本的停车管理器模块
当车辆驶入停车场时 a）捕获要停车的车辆信息和停车场编号 b）将该批次标记为不可用
当车辆离开停车场时， 捕获要清空的停车场编号， 并将该批次标记为可用
然后，在旅途中玩得开心。 * /
#include<stdio.h>
#define YOU_ARE_TRAPPED_BY_THE_BIG_BAD_GREEN_SCARY_MONSTER ({printf("HA HA HA, You didn't read and follow the inline comments !!\nNow stand up, jump 3 times, then sit down, and read all the comments again and do the min code modif to make me go away, else i won't let you escape the parking lot ... hoo ha ha ha ha >-)\n"); updateVehicleParkingInfo=1;})
#include<stdlib.h>
struct Vehichle{
char vecType[100]; //type of vehicle eg suv,mpv and more...
char plateNo[10]; //number plate of the vehicle
float hours; //???
};
struct Parking{
int parkNo ; //parking lot num
bool availability; //Is tbis parking space available? Yes/No
};
struct VehicleParkingInfo{
struct Vehicle vehicle; //vehicle info
struct Parking parking; //corresponding parking info
};
//maximum number of parking lots that the parking space has
#define MAX_PARKING_LOTS 10
//parking lot avaialble flags
#define PARKING_LOT_AVAILABLE true
#define PARKING_LOT_UNAVAILABLE false
//flags for vehicle coming in or leaving
#define VEHICLE_ENTERING true
#define VEHICLE_LEAVING false
void main(){
int updateVehicleParkingInfo; //flag indicating that user wants to update parking info.
int vehicleDirection; //flag for indicating whether the vehicle is coming in or going out of the parking
int parkingIdx; //index of the parking lot to fetch values from.
//array for info about all the parking lots
struct VehicleParkingInfo vehicleParkingInfo[MAX_PARKING_LOTS];
//initialize the parking & vehicle info of all the parking lots to zeros
memset(vehicleParkingInfo,0,MAX_PARKING_LOTS*sizeof(VehicleParkingInfo));
//for each parking lot, mark it as available and assign parking lot numbers serially
for(parkingIdx = 0; parkingIdx < MAX_PARKING_LOTS; parkingIdx++){
vehicleParkingInfo[parkingIdx].parking.parkNo = parkingIdx;
vehicleParkingInfo[parkingIdx].parking.availability = PARKING_LOT_AVAILABLE;
}
//get user's input if parking info needs to be updated or it is time to close and go home
printf("Update parking info? Enter 0 to end");
scanf("%d",&updateVehicleParkingInfo);
/*
**** SENTINEL LOOP ****
Continue updating the parking info until the user wants to even for unlimited number of times.
Stop only when user enters a specific value i.e. 0.
*/
while(updateVehicleParkingInfo != 0){
printf("vehicle direction? 1 for entering, 0 for leaving:");
scanf("%d",&vehicleDirection);
if(vehicleDirection == VEHICLE_ENTERING){
do{
printf("Please enter parking Number:");
scanf("%d",&parkingIdx);
//*** CRASH ALERT!!! *** Following code can crash if parkingIdx is < 0, or >= MAX_PARKING_LOTS
//TODO: (1) Add sanity check for parkingIdx (2) Add corrective steps if sanity check fails
//if parking is not available, print an error message
if(vehicleParkingInfo[parkingIdx].parking.availability == PARKING_LOT_UNAVAILABLE){
//TODO: change the below messages to fine-tune fun, humor, teasing etc levels (remember humor setting of TARS from Interstellar?)
printf("There is some other vehicle parked in this parking lot, please enter another parking lot number\n");
printf("BTW, I know which lots are available, but I won't tell you ... hehehe >-) \n, keep trying ...hoo hoo hooo\n");
}
//check if the requested parking lot is available, if yes, then take further actions, else request a new parking lot number
}while(vehicleParkingInfo[parkingIdx].parking.availability == PARKING_LOT_UNAVAILABLE);
printf("Yipee, this parking lot is available\n");
//mark this parking lot number as being used so that another vehicle cannot come here.
vehicleParkingInfo[parkingIdx].parking.availability = PARKING_LOT_UNAVAILABLE;
//get vehicle type info and
// *** CRASH ALERT!!! *** The scanf below will crash if the user enters more 99+ characters (buffer overflow)
// Best is to use fgets or getline with the stdin as the stream.
// Ref https://stackoverflow.com/questions/4023895/how-do-i-read-a-string-entered-by-the-user-in-c
// TODO: Replace below scanf() with a better/safer implmentation
printf("Enter Vehicle Type etc: suv,mpv and more:");
scanf("%s",vehicleParkingInfo[parkingIdx].vehicle.vecType);
//TODO: other steps.
}
if(vehicleDirection == VEHICLE_LEAVING){
do{
printf("Please enter parking Number:");
scanf("%d",&parkingIdx);
//*** CRASH ALERT!!! *** Following code can crash if parkingIdx is < 0, or >= MAX_PARKING_LOTS
//TODO: (1) Add sanity check for parkingIdx (2) Add corrective steps if sanity check fails
//if parking is available, print an error message
if(vehicleParkingInfo[parkingIdx].parking.availability == PARKING_LOT_AVAILABLE){
printf("It appears that the parking lot number is incorrect, please enter correct parking lot number\n");
}
//check if the requested parking lot is available, if yes, then request a new parking lot number, else proceed further
}while(vehicleParkingInfo[parkingIdx].parking.availability == PARKING_LOT_AVAILABLE);
printf("Bye bye, drive safely\n");
//mark this parking lot number as available for other incoming vehicles.
vehicleParkingInfo[parkingIdx].parking.availability = PARKING_LOT_AVAILABLE;
}
//get user's input if parking info needs to be updated or it is time to close and go home
printf("Update parking info? Enter 0 to end");
scanf("%d",&updateVehicleParkingInfo);
//TODO: remove the following line of code before running the program
YOU_ARE_TRAPPED_BY_THE_BIG_BAD_GREEN_SCARY_MONSTER;
//go back to while loop,
//check if the vehicle parking info needs to be updated,
//break if the user has entered 0
}//end of the Sentinel loop
//the above loop will run indefinitely. The user has quite a lot of ways to come out of the loop
//(1) Enter the sentinel value '0', (easiest path)
//(2) Somehow stop the program e.g. by banging his/her head really hard on the computer such that computer breaks .. etc
}//end of main()