C ++ —指向结构数组的指针，该结构包含指向无法正常工作的类数组的指针

Question

I'm working on a problem that involves reading from a file, saving the information to an array of structs and classes, and then displaying the information. I've omitted some function definitions for the sake of trying to be brief. The applicable areas of my code are as follows:

void getInputFile (RentalAgency *ptr) {
int a=0, b=0, c=0;
int tempYear;
float tempPrice;
char tempMake[264], tempModel[264];
bool tempAvailable;
ifstream inputStream;
int *zipCodePtr=(*ptr).zipcode; //create pointer to struct zipcodes
RentalCar *inventoryPtr=(*ptr).inventory; //create pointer to an array of classes



while (a<3) {

On output, it should look like this:

Hertz 93619
2014 Toyota Tacoma, $115.12 per day, Available: 1
2012 Honda CRV, $85.1 per day, Available: 0
2015 Ford Fusion, $90.89 per day, Available: 0
2013 GMC Yukon, $110.43 per day, Available: 0
2009 Dodge Neon, $45.25 per day, Available: 1
Alamo 89502
2011 Toyota // more information is posted similar to above

Instead, there seems to error with my ptr variable, as it displays:

Hertz 93619
2014 Toyota Tacoma, $115.12 per day, Available: 1
2012 Honda CRV, $85.1 per day, Available: 0
2015 Ford Fusion, $90.89 per day, Available: 0
2013 GMC Yukon, $110.43 per day, Available: 0
2009 Dodge Neon, $45.25 per day, Available: 1
Alamo
89502 //It stops printing here

In my attempt to resolve this issue, I noticed upon incrementing ptr and displaying the agency name, it first printed Hertz, then Alamo, then 89502 (as opposed to the next name), then gibberish. Clearly there is an issue with saving information from the input file (which FYI, is similar to the format of the display) for the second and third agencies. Any assistance is greatly appreciated. C relates to the size of the inventory array, b relates to the size of the zipcode array, and a relates to 3 agencies I'm trying to save and display.

Answer 1

You need to reset b and c each time through the outer loop in both routines. What's happening is (in both the input and output routine) b and c have the value of 5 after the first time through the outer ( a ) loop.

You can solve the problem by moving the initialization of b and c into the while loop.

while(a < 3)
{
   int b = 0, c = 0;
   // ... rest of code ...
}

Answer 2

If it's stopping earlier than expected, it seems like it's a problem coming from the loop condition.

If you're getting gibberish, it seems like a problem with your indices where you're reaching outside the array which is why you're getting garbage values.

It would also help in terms of readability if you had more descriptive variable names. a? b? c?