2

If I give my program the txt file: 

BB MB 150 570 2 240 570 3 360 570 0 FB E T

It reads it in incorrectly and instead reads it as 

BB 150 0 0 240 570 2 360 570 3 0 570 0 MB FB E T

Here is a simplified version of what I am using to read this:

string one,two,three,four; ifstream file; filename+=".txt";//filename is a string file.open(filename.c_str()); while (file >> one >> two>>three&&one!="MB") { //do stuff with it here }

and so on. Can someone explain why two and three are initially being set to 0?

Full version of code:

To read:

void load(string filename) { string one,two,three,four; ifstream file; filename+=".txt"; file.open(filename.c_str()); //blocks //backblock list while (file >> one >> two>>three&&one!="MB") { backBlockList.push_back( Block(atoi(two.c_str()),atoi(three.c_str()),atoi(one.c_str()))); } while (file >> one >> two>>three&&one!="FB") { midBlockList.push_back( Block(atoi(two.c_str()),atoi(three.c_str()),atoi(one.c_str()))); } while (file >> one >> two>>three&&one!="E") { foreBlockList.push_back( Block(atoi(two.c_str()),atoi(three.c_str()),atoi(one.c_str()))); } while (file >> one &&one!="T") { enemyList.push_back(Enemy(atoi(one.c_str()))); //loads waypoints while (file >> one>>two ) { enemyList.at(enemyList.size()-1).addWaypoint( atoi(one.c_str()),atoi(two.c_str())); } while(file>>one>>two>>three>>four) { textBlockList.push_back( TextBlock(atoi(one.c_str()),atoi(two.c_str()))); textBlockList.at( textBlockList.size()-1).setText(three); textBlockList.at( textBlockList.size()-1).setRange(atoi(four.c_str())); } } }

To write:

void printOut(string filename ) { cout<<"printing "<<endl; ofstream myfile; filename+=".txt"; myfile.open (filename.c_str()); myfile << "BB\n"; //prints out blocks cout<<"printing backblocks"; unsigned int i = 0; for( i = 0; i<backBlockList.size(); i++) { backBlockList.at(i).print(myfile); } cout<<" printed "<<i<<endl; cout<<"printing midblocks"; myfile << "MB\n"; for( i = 0; i<midBlockList.size(); i++) { midBlockList.at(i).print(myfile); } cout<<" printed "<<i<<endl; cout<<"printing foreblocks"; myfile << "FB\n"; for( i = 0; i<foreBlockList.size(); i++) { foreBlockList.at(i).print(myfile); } cout<<" printed "<<i<<endl; cout<<"printing enemies "<<endl; myfile<<"E\n"; for( i =0; i<enemyList.size(); i++) { enemyList.at(i).print(myfile); } cout<<"printing text"; myfile<<"T\n"; for( i =0; i<textBlockList.size(); i++) { if(textBlockList.at(i).complete()) textBlockList.at(i).print(myfile); } cout<<" printed "<<i<<endl; cout<<"printing other"<<endl; //Additional stuff goes here EX BACKGROUND myfile.close(); cout<<"printing done"; }

Block write:

void Block::print(ofstream & file) { file << x; file << " "; file<< y; file<< " "; file<< Type; file<< " \n"; }

TextBlock write:

void TextBlock::print(ofstream & file) { file<< x; file<<" "; file<< y; file<<" "; file<< text; file<<" "; file<<range; file<<" \n"; }

Enemy write:

void Enemy::print(ofstream & file) { file<<type; for(unsigned int i =0; i<X.size()-1; i++) { file<<" "; file<< X.at(i); file<<" "; file<< Y.at(i); } file<<"\n"; }
Improve this question
10
  • What is it that you're trying to achieve with this? Commented Jun 9, 2013 at 18:45
  • I am saving values in a txt file with one program and then loading them to create objects with another Commented Jun 9, 2013 at 18:45
  • Have you heard of serialization , just convert the object to binary form and read it :) Commented Jun 9, 2013 at 18:48
  • There is no possible way the string "0" could be produced by this code. Show us your actual code, not your simplified version. Commented Jun 9, 2013 at 18:56
  • full read/write code posted Commented Jun 9, 2013 at 19:01

3 Answers 3

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2

I would have expected it to read the file as:

BB MB 150 570 2 240 570 3 360 570 0 FB E T

because it's always reading three strings at a go. If you want to always read three strings you may wish to pad your MB and BB indicators with dummy 0s to read (For example MB 0 0).

It may help to realize that

cin >> a >> b >> c; is no different from cin >> a; cin >> b; cin >> c; when it comes to handling newlines.

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Comments

1

The reason for the number triples that you got:

150 0 0 240 570 2 360 570 3 0 570 0

is following: Your input only gets read from the first loop:

while (file >> one >> two>>three&&one!="MB")

Like following:

Loop | one | two | three | atoi | atoi | atoi | | | | one | two | three ---------------------------------------------- 1 | BB | MB | 150 | 0 | 0 | 150 2 | 570 | 2 | 240 | 570 | 2 | 240 3 | 570 | 3 | 360 | 570 | 3 | 360 4 | 570 | 0 | FB | 570 | 0 | 0 5 | breaks the loop because three can't be read

The last three columns in the table are the observed number triples.

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0

The line

file >> one >> two>>three&&one!="FB"

reads three strings from a file instead of one.

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