Try/Catch/Throw...Can't get data read in right, and stuck in an infinite loop!

[aemado]

I am trying to read in several lines, each should have exactly 5 pieces of data. I am using try/catch/throw to determine if the data is in the correct format, and trying to use iss to separate the parts. However, this is my first time using both, and I am pretty certain that I am missing something obvious. Firstly, by debugging, I found that the first piece of data is being checked in the second case, giving me errors. I believe I may need to read in more from the iss>> than just the one, but I am lost. Any suggestions?? Here is my code:

	ifstream indata;
	ifstream indata2;
	string instring;
	string instring2;
	istringstream iss_string;
	istringstream iss_string2;
	string data[5];
	string data2[5];
	int count = 0;
	int count2 = 0;
	int datacount = 0;
	int offset;
	int offset2;

	indata.open("student.data");
	if(!indata){
		cout<<"student.data file could not be opened.";
		exit(1);}
	
	while(indata){
		getline(indata, instring);

		try{
			while(instring != "0"){
				iss_string.str(instring);
				iss_string >> data[count];
				datacount++;
				offset = iss_string.tellg();
				while(offset >= 0){
					switch(count){
						case 0:
							if(data[count].length() != 9){
								throw 0;
								break;
							}
							for(int i=0; i < (data[count].length()); i++){
								if(!isdigit(data[count][i])){
									throw 0;
									break;
								}
							}
						case 1:
							if(data[count].length() > 30 || data[count].length() < 1){
								throw string("Invalid number of characters in Last Name of student.data file");
								break;
							}
							for(int i=0; i<data[count].length(); i++){
								if(!isalpha(data[count][i])){
									throw string("Invalid characters in Last Name of student.data file");
									break;
								}
							}
					
						case 2:
							if(data[count].length() > 30 || data[count].length() < 1){
								throw string("Invalid number of characters in First Name of student.data file");
								break;
							}
							for(int i=0; i<data[count].length(); i++){
								if(!isalpha(data[count][i])){
									throw string("Invalid characters in First Name of student.data file");
								}
							}
					
						case 3: 
							if(data[count].length() != 2){
								throw string("Invalid number of characters in Major of student.data file");
								break;
							}
							for(int i=0; i<data[count].length(); i++){
								if(!isalpha(data[count][i])){
									throw string("Invalid characters in Major of student.data file");
								}
							}
					
						case 4: 
							if(data[count].length() != 2){
								throw string("Invalid number of characters in Year of student.data file");
							}
							for(int i=0; i<data[count].length(); i++){
								if(!isalpha(data[count][i])){
									throw string("Invalid characters in Year of student.data file");
								}
							}
							//break;
					}
				
				}
			}

			count++;
			iss_string>>data[count];
			offset = iss_string.tellg();
			if(datacount != 5){
				throw string("Invalid number of items in line of student.data.");
				
				//break;
			}
			getline(indata, instring);
			iss_string.clear();
			count = 0;
		}
		catch(int x){
			cout<<"Invalid ID number in student.data file";
			exit(1);
		}
		catch(string s){
			cout<< s <<endl;
			exit(1);
		}
	}
	indata.close();

[weaknessforcats]

Start by reducing the size of your try block.

A try block should cover one or may be two statements.

Also, a parser is built using a finite-state automaton and not a giant switch staement. You might read: http://bytes.com/forum/thread660060.html.