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digitalmars.D.learn - User input readline || readf

reply "kerze" <kurz.andi gmx.ch> writes:
Hy, i'm new   D and i come from python.
Sorry for my engish, i understand good, but i write like a cow 
spanish.

I make a little programm to add human's name and age and a 
function to write out alls humans in the list.

Here is the source:

http://dpaste.dzfl.pl/0a0da462225d

The problem is, it writes instant "Name: Age:" at the standart 
output.

I'm little confuse about readf and readline, what to use. or its 
the failure in write ?

I hope anybody can help me, as long as anybody understand me and 
my problem. ;)

Greetings from Swiss.

Kerze
Apr 23 2015
next sibling parent "kerze" <kurz.andi gmx.ch> writes:
hmm the paste is away ?!? here i post my source one more time.

[code]
import std.stdio;
import std.string;

struct Human {
     string name;
     ushort age;
};


void print_human_list(Human[] human_list){
     foreach(human; human_list){
         writeln(human.name);
	writeln(human.age);
     }
     writeln("");
}



void add_new_human(Human[] human_list){
     ushort age;                               //
     write("Name: ");                          //  The Output is
     string name = strip(stdin.readln());      //  Name: Age:
     write("Age: ");                           //  And the Error
     readf(" %u", &age);                       //  
std.conv.ConvException /usr/include/dlang/ldc/std/conv.d(1968):
     Human tmp_human = {name, age};            //  Unexpected 's' 
when converting from type LockingTextReader to type uint
     human_list ~= tmp_human;
}



int main(){
     Human[] human_list;
     char choice;

     for(;;){
         writeln("A)dd New Human.");
         writeln("P)rint Human List.");
	writeln("Q)uit.");
	write(": ");
         readf("%c", &choice);
	switch(choice){
             case('A') : add_new_human(human_list);
	    case('P') : print_human_list(human_list);
	    case('Q') : return 0;
	    default   : continue;
	}
     }
}
[/code]
Apr 23 2015
prev sibling next sibling parent Steven Schveighoffer <schveiguy yahoo.com> writes:
On 4/23/15 1:17 PM, kerze wrote:

 The problem is, it writes instant "Name: Age:" at the standart output.


readf reads the element from the stream, and NOTHING MORE, it leaves the 
newline on the stream.

So the next readf then reads the newline as a string. You can fix this 
by using readf(" %s"), which means "read any whitespace, then my data".

-Steve
Apr 23 2015
prev sibling next sibling parent reply "Jacques =?UTF-8?B?TcO8bGxlciI=?= <jacques.mueller gmx.de> writes:
The paste is still there.

readf leaves the \n from pressing enter in stdin, which gets read
by the next function that's accessing it.

I answered a similiar question in another thread:
http://forum.dlang.org/post/jwxfaztgsyzwqpzajqmf forum.dlang.org

I see two other mistakes in your code as well:
1. I'm pretty sure you want to pass print_human_list and 
add_new_human a reference to the human_list array. Just add "ref" 
before "Human[] human_list".

 void print_human_list(ref Human[] human_list)


2. In D there exists something called switch fallthrough. Just 
add a "break;" after each case and only the matching block will 
be executed.

case('A'):
    add_new_human(human_list);
    break;


Willkommen in der D Community. ;)
Apr 23 2015
parent "kerze" <kurz.andi gmx.ch> writes:
 Willkommen in der D Community. ;)


So many Thanks  Steven and Jacques, answer's more than a only; 
"do this" ;)
Apr 23 2015
prev sibling parent reply "Dennis Ritchie" <dennis.ritchie mail.ru> writes:
On Thursday, 23 April 2015 at 17:18:01 UTC, kerze wrote:

 Hy, i'm new   D and i come from python.
 Sorry for my engish, i understand good, but i write like a cow 
 spanish.

 I make a little programm to add human's name and age and a 
 function to write out alls humans in the list.

 Here is the source:

 http://dpaste.dzfl.pl/0a0da462225d

 The problem is, it writes instant "Name: Age:" at the standart 
 output.

 I'm little confuse about readf and readline, what to use. or 
 its the failure in write ?

 I hope anybody can help me, as long as anybody understand me 
 and my problem. ;)

 Greetings from Swiss.

 Kerze


I can offer, for example, such an option:

-----
import std.conv;
import std.stdio;
import std.string;
import std.typecons;

Tuple!(string, ushort)[] humanList;

void printHumanList() {

	foreach (e; humanList) {
		writeln(e[0]);
		writeln(e[1]);
	}
}

void addNewHuman(){

	write("Age: ");
	ushort age = readln.strip.to!ushort;

	write("Name: ");
	string name = readln.strip;

	humanList ~= tuple(name, age);
}



void main(){

	char choice;

	for(;;) {

		writeln("A)dd New Human.");
		writeln("P)rint Human List.");
		writeln("Q)uit.");
		write(": ");

		choice = readln.strip.to!char;

		switch (choice){
		case('A'):
			addNewHuman;
			break;
		case('P'):
			printHumanList;
			break;
		case('Q'):
			return;
		default:
			continue;
		}
	}
}
Apr 23 2015
parent "Dennis Ritchie" <dennis.ritchie mail.ru> writes:
It also works:

-----
import std.conv;
import std.stdio;
import std.string;

struct Human {
	string name;
	ushort age;
}

void print_human_list(Human[] human_list) {

	foreach(human; human_list) {
		writeln(human.name);
		writeln(human.age);
	}
	writeln();
}

void add_new_human(ref Human[] human_list) {

	write("Name: ");
	string name = readln.strip;

	write("Age: ");
	ushort age = readln.strip.to!ushort;

	Human tmp_human = {name, age};
	human_list ~= tmp_human;
}

void main() {

	Human[] human_list;
	
	for(;;) {

		writeln("A)dd New Human.");
		writeln("P)rint Human List.");
		writeln("Q)uit.");
		write(": ");

		char choice = readln.strip.to!char;

		switch (choice) {
		case('A'):
			add_new_human(human_list);
			break;
		case('P'):
			print_human_list(human_list);
			break;
		case('Q'):
			return;
		default:
			continue;
		}
	}
}
-----
http://ideone.com/0cS7Y4
Apr 23 2015