C++ Looping through a input Stream (Help)

[TheGosuStandard]

Hello, Not sure if asking coding questions is still allowed here, if it's not let me know. I'm trying to figure out how to compare an input string variable from the user to a input stream string variable  (input stream contains 4 integers and 1 string). Since there is no order for the listing and what the user input I am having trouble when the user inputs incorrect data, otherwise if they put in a matching string it will output the information for that line.

 

The if condition where (popVoteState == stateName) will only work as long as the input is correct, however if the input is incorrect it doesn't prompt the user to reenter it or it would go line by line until it finds the input by prompting X amount of times until you reach it. 

 

How would I be able to search through the file for the user input to match, if it does match output the values associated for the string and if it doesn't match a state due to incorrect input (after searching through the file) it should re-prompt the user to input a correct state. 

    ifstream election12X, elecVote10X;

    election12X.open("elect12.csv");
    elecVote10X.open("ev10.csv");

    if (election12X.fail() && elecVote10X.fail())
    {
        cout << "File open failed" << endl;
        exit(1);
    }
    //Assert: "elect12.csv" and "ev10.csv" is open for input

    int numRegion;
    bool done = false;

    do
    {
        cout << "Enter the number of regions" << endl;
        cin >> numRegion;
    } while(numRegion < 0);

    for (numRegion; numRegion > 0; numRegion--)
    {
        cout << "Enter the state name" << endl;
        string stateName;
        cin >> stateName;

        while (election12X >> popVoteObama >> popVoteRomney >> popVoteOthers >> popVoteTotal >> popVoteState)
        {
            if (popVoteState == stateName)
            {
                cout << popVoteObama << endl;
            }
            if (election12X.eof() && popVoteState != stateName)
            {
      			cout << "Reeneter a state";
      			cin >> stateName;
            }
        }
        election12X.clear();
        election12X.seekg(ios::beg);
        //cout << endl;}
    }

    election12X.close();
    elecVote10X.close();

 

[2FA]

I think your issue lies in the fact that you are using two if statements. Wouldn't it be better to use else if for the second condition? I know C, not C++ but if I'm thinking right that might be the issue.

[TheGosuStandard]

1 minute ago, DeadEyePsycho said:

I think your issue lies in the fact that you are using two if statements. Wouldn't it be better to use else if for the second condition? I know C, not C++ but if I'm thinking right that might be the issue.

It does the same output for else if, this is the output with one correct input variable (as it searches through everything) and two incorrect variables (doesn't re-prompt)

 

Enter the number of regions
3
Enter the state name
NY
4485741
Enter the state name
aa
Enter the state name
aa

[2FA]

2 minutes ago, TheGosuStandard said:

It does the same output for else if, this is the output with one correct input variable (as it searches through everything) and two incorrect variables (doesn't re-prompt)

 

Enter the number of regions
3
Enter the state name
NY
4485741
Enter the state name
aa
Enter the state name
aa

What about an ordinary else statement?

[Mr_KoKa]

Have you checked if you read from file correctly? CSV format is strings delimited with comma character , if value contain special characters, it is closed in ".

When you read from stream using >> operator it will read until white space or character that is not matching variable, so after first read to popVoteObama it encounters comma character, and when you do second read by >> operator, it tries to read from that coma to integer, it will fail, and stream will be set bad flag.

 

Or your file is not csv format, can you give example of file?

 

I made example:

#include <fstream>
#include <iostream>

int main(){
	
	std::ifstream csv("file.csv");
	
	if(csv.good()){
		
		int a = 123;
		int b = 123;
		std::string c = "123";
		
		bool result;
		
		result = static_cast<bool>(csv >> a);
		std::cout << "Read: " << (result? "OK" : "FAILED") << " - [" << a << "] - streem state: " << (csv.good()? "GOOD" : "BAD") << std::endl;
		result = static_cast<bool>(csv >> b);
		std::cout << "Read: " << (result? "OK" : "FAILED") << " - [" << b << "] - streem state: " << (csv.good()? "GOOD" : "BAD") << std::endl;
		result = static_cast<bool>(csv >> c);
		std::cout << "Read: " << (result? "OK" : "FAILED") << " - [" << c << "] - streem state: " << (csv.good()? "GOOD" : "BAD") << std::endl;	
		
	} else {
		std::cout << "Unable to open file." << std::endl;
	}
	
	return 0;
}

for file, that contains:

1,2,Test

it will output:

Read: OK - [1] - streem state: GOOD
Read: FAILED - [0] - streem state: BAD
Read: FAILED - [123] - streem state: BAD

 

For file that contains:

1 2 Test

Output will be:

Read: OK - [1] - streem state: GOOD
Read: OK - [2] - streem state: GOOD
Read: OK - [Test] - streem state: BAD

The last bad is because good returns false because of EOF.

[TheGosuStandard]

7 minutes ago, DeadEyePsycho said:

What about an ordinary else statement?

I believe I want a condition as a comparison, else would indicate that there is no other condition

 

4 minutes ago, Mr_KoKa said:

Have you checked if you read from file correctly? CSV format is strings delimited with comma character , if value contain special characters, it is closed in ".

When you read from stream using >> operator it will read until white space or character that is not matching variable, so after first read to popVoteObama it encounters comma character, and when you do second read by >> operator, it tries to read from that coma to integer, it will fail, and stream will be set bad flag.

 

Or your file is not csv format, can you give example of file?

It's an excel file there are spaces between each variable (doesn't show it in excel, in wordpad it does).  It reads from the file correctly if the only condition set is finding a match, however the issue occurs (or at least I am unsure how to set it up) for when the user input doesn't match. 

elect12.csv

[Mr_KoKa]

Seems like election12X is never EOF inside of loop.

 

Edit: It is because of that new line at the end of file. first stream encounters last new line character and then it reads it and probably fails to write to popVoteObama

[2FA]

10 minutes ago, TheGosuStandard said:

I believe I want a condition as a comparison, else would indicate that there is no other condition

 

The reason I suggested it was because if the condition for the if statement is not met, then you automatically presume the information entered is incorrect for a comparison since you have a predefined list of state names.