How to read lines of a file into an array of structs

Question

I am trying to read a file which contains the arrival time and burst time of 22 processes in every line.I am trying to store these values into an array of structs so I can update them everytime a process gets a CPU cycle.The read is not working successfully though.Help me figure out what I am missing. The file which is a text file looks like: 30 0.78 \n 54 17.28 \n 97 32.82 \n . . . .

#include<iostream>
#include<fstream>

using namespace std;        
const int process_cnt=22;

struct process{        
          int at;
          float bt;
          float rt;
};

process init_q[process_cnt],ready_q[process_cnt];        
void getData(ifstream& inData,process init_q[]);

int main(){        
    ifstream inData;        
    getData(inData,init_q);                
    cout<<"Test";        
    return 0;
}

void getData(ifstream& inData,process init_q[]){                        
    inData.open("input.txt");        
    while(inData){          
        inData>>init_q->at>>init_q->bt;
        cout<<init_q->at<<" "<<init_q->bt<<endl;//check if read was succesful           
    }
    inData.close();         
}

Is this a binary or text file? Are there new lines at the end? Have you tried this code, if so what happens? — doctorlove
– doctorlove, Commented Nov 7, 2016 at 13:49
You're using a somewhat unfortunate shortning of "number" to "no". Consider using process_cnt instead of no_process. It confused me (unnecessarily) for a couple of seconds. — Jonas Byström
– Jonas Byström, Commented Nov 7, 2016 at 13:53
If you are filling queues why don't you use appropriate datatypes? This code doesn't "feel" like C++ at all... — Simon Kraemer
– Simon Kraemer, Commented Nov 7, 2016 at 14:02
Simon Kraemer I am new to programming and I have been reading c++ just for the past 1 month.So any datatype recommendation, criticisms, corrections are absolutely acceptable.That will make me a better future developer. — jenthu
– jenthu, Commented Nov 7, 2016 at 14:20

woockashek · Accepted Answer · 2016-11-07 13:50:06Z

2

Probably what you are missing is the index of current array entry:

void getData(ifstream& inData, process init_q[]) {
    inData.open("input.txt");
    int index = 0;
    while (inData) {
        process *entry = init_q[index++];
        inData >> entry->at >> entry->bt;
        cout << entry->at << " " << entry->bt << endl;//check if read was succesful
    }
    inData.close();
}

I skipped the part checking whether the current index is lower than your const 22.

edited Nov 7, 2016 at 13:50

answered Nov 7, 2016 at 13:44

woockashek

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3 Comments

jenthu Over a year ago

I am getting an error "cannot convert process to process in initialization" for the pointer though.Is that legit?

doctorlove Over a year ago

So, a new error message now you have changed the code? WHat exactly does the error say, and are you sure this isn't a new question?

jenthu Over a year ago

I am still just trying to figure out how to store the values in each line of the text file to the arrival time and burst time of the init_q.

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