Kirk Garvey wrote:

Hi,

As an experienced 'C' programmer but C++ novice I am wondering what is the best programming practice for standard input/output when programming C++, should one use 'printf()' and 'sprintf()' or 'cout' and 'cin'? Or is it down to personal preference?

Personally I use both. When I just want to simply print unformatted data I use cout but if I have much formating, especially if part of a line is formated significantly different than another part I find printf much easier. Along the same lines I have found that for reading data that has a complex format that scanf is easier than cin. I have also noticed that some C programmers aren't even aware of the power of the scanf and printf. I'm not as expert with cin and cout as I am with printf and scanf but one time I wrote code to read in a data file in both C and C++ and found that the scanf did it in one scan statement where with cin I had to read the whole line into a buffer and do significant processing to store the values. If anyone is interested I can post the code and they can show me how it could be done easier in C++ -- Chris W Not getting the gifts you want? The Wish Zone can help. http://thewishzone.com

Kirk Garvey wrote:

I for one would certainly be interested in seeing the code, it could serve as an example when to choose one I/O method over another.

Ok first the scanf method struct record{ char city[4]; char date[5]; char time[4]; float AirTemp; float WindSpeed; float WindDirection; float RainFall; }; int main() { char c; FILE *out; FILE *in; out = fopen("prog1.new", "wb"); in = fopen("prog1.dat", "rt"); record r; /*structure to store data to be written to binary file*/ while(fscanf(in, "\"%4s\",\"%5s\",%4s,%f,%f,%f,%f,\n", &r.city, &r.date, &r.time, &r.AirTemp, &r.WindSpeed, &r.WindDirection, &r.RainFall)!= EOF){ fwrite(&r, sizeof(record), 1, out); } return 0; } Then the C++ which I am sure could be much better since I knew very little about when I wrote this. int main() { FILE *out; /*binary file to be created*/ out = fopen("prog1.bin", "wb"); string line; /*memory to store data from text file one line at a time*/ record WeatherData; /*structure to store data to be written to binary file*/ ifstream in("prog1.dat"); /*input stream to read text file*/ while(in){ in >> line; strncpy(WeatherData.city, (line.substr(1,4)).c_str(), 4); strncpy(WeatherData.date, (line.substr(8,5)).c_str(), 5); strncpy(WeatherData.time, (line.substr(15,4)).c_str(), 4); line = line.substr(20); int begin = 0; int end = line.find(','); WeatherData.AirTemp = atof((line.substr(begin, end - begin)).c_str()); begin = ++end; end = line.find(',', end); WeatherData.WindSpeed = atof((line.substr(begin, end - begin)).c_str()); begin = ++end; end = line.find(',', end); WeatherData.WindDirection = atof((line.substr(begin, end - begin)).c_str()); begin = ++end; end = line.find(',', end); WeatherData.RainFall = atof((line.substr(begin, end - begin)).c_str()); fwrite(&WeatherData, sizeof(record), 1, out); } return 0; } Finally some sample data. . . "WASH","01/17",1745,0.0,0.0,0.0,0.00, "CAMA","01/17",1030,25.9,1.8,254.0,0.00, "CAMA","01/17",0945,26.2,0.4,323.0,0.00, "CAMA","01/17",1100,26.2,0.9,107.0,0.00, "SEIL","01/17",1030,26.2,2.2,152.0,0.00, "SEIL","01/17",1045,26.2,3.1,206.0,0.00, "CAMA","01/17",0930,26.4,0.2,331.0,0.00, "CAMA","01/17",0900,26.4,1.1,226.0,0.00, "CAMA","01/17",1015,26.4,1.3,305.0,0.00, "BUFF","01/17",0800,26.4,3.1,30.0,0.00, "CAMA","01/17",1000,26.6,1.1,6.0,0.00, -- Chris W Not getting the gifts you want? The Wish Zone can help. http://thewishzone.com

Yupiii...........!!! Thanks Cincai.... It runs properly now. Now, I feel free to do my further practice with GNU C++. I bought GNU C++ for Linux (by Tom Swan). I am goint to learn from this book. Your help in my first step is very usefull. I have modified my code. I moved the classes into header file, do "include "bsamba.h" (and also for the other header file) and compile it again with "g++ -I ./ liss.cpp". and everything as expected. Thanks Cincai.... Thank you. --- Cincai Patron wrote:

On Thursday 30 September 2004 21:16, Prabu Subroto wrote:

...

I am still confused. Sorry I am a really beginner in GNU C++. 1. May I make 2 classes in one file?

Yes.

...

2. header is somewhat like this : "#include .

In C++, drop .h for system headers -- it's the newer standard. You can still append .h, but gcc will warn you.

...

I am confused how should the header file of my "menu" class for registering "samba" class in the "menu" class?

Could you give me an example of the header file of my "menu" class please....?

Class "menu" needs "samba", but you define "samba" after "menu". One way is as Paul suggested: class samba {...}; class menu {...};

The other whould be to declare samba first: class samba; class menu {...}; class samba {...};

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