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I need help with arrays and structures.

Fedelway (13)
Hello cplusplus community. I was trying to solve a little problem from a tutorial to learn c++ and i've come to an impassable wall (for me of course :D).
In the assignment we had to create a small database using structures and arrays and then search through it.

My problem comes when i try to assign names to the arrays. I get this error line: incompatible types in assignment of 'const char [5]' to 'char [20]'
And it variates depending on the length of the name.

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 struct persona
{
	char nombre[20];
	int telefono;
} lista[10];

int main ()
{
	// asignacion de valores a la estructura
	lista[1].nombre = "jose";
	lista[1].telefono = 12345678;
	lista[2].nombre = "juan";
	lista[2].telefono = 34265891;
	lista[3].nombre = "federico";
	lista[3].telefono = 64817592;
	lista[4].nombre = "facundo";
	lista[4].telefono = 12363852;
	lista[5].nombre = "asdfjklñ";
	lista[5].telefono = 58924719;
	lista[6].nombre = "gabriel";
	lista[6].telefono = 52758195;
	lista[7].nombre = "marcos";
	lista[7].telefono = 78298761;
	lista[8].nombre = "pelotudo";
	lista[8].telefono = 42402098;
	lista[9].nombre = "hola";
	lista[9].telefono = 39684489;
	lista[10].nombre = "lalala";
	lista[10].telefono = 64573892;


It is written in spanish but i don't think there is a problem with that.

Can you help me?
Yanson (885)
keskiverto (10363)
That is not the assignment that you are looking for.

What you try to do now is essentially:
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const char * a;
char * b;
b = a;

What you should do is to copy elements from one array into an another. Check <cstring> for C-string copying functions. Better yet, replace char arrays with std::string. It has a copy assignment operator.
billywilliam (79)
The differences between the data type "const char[5]" and the data type "char[20]" seem negligible to humans, but to the compiler, trying to set a variable of date type "const char[5]" to a variable of data type "char[20]" makes about as much sense as
int x='a';

"jose" is const char[5] because the string literal "jose" will always be "jose".

I ran into the same problem when I started programming and the explanation didn't make sense to me until much later, but fortunately the fix is simple.

Look at this function: http://www.cplusplus.com/reference/cstring/strcpy/
Correctly implementing it in your code would look like
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strcpy(lista[1].nombre,"jose");
lista[1].telefono=1234567;
strcpy(lista[2].nombre,"juan");

etc...
Last edited on
Fedelway (13)
Thanks guys for the help, that fixed my problems.

I have one question. Keskiverto said that i should replace char arrays with std::string. is that using the function strcpy?

I also have another problem with this little program and i can't find where it is.

After fixing the const char issue i ran the program but i failed to do so. When i search for any name or telephone number [except for the first one in the list(jose - 12345678)] i get an infinite amount of prints with the results.

Can you help me again?

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//creado por fedelway
#include <string.h> //para la funcion strcmp y strcpy
#include <stdlib.h> //para la funcion exit
#include <iostream> //para cout y cin
using namespace std;

//prototipos de funciones
void buscarN(char name[20]);
void buscarT(int t);

//creación de estructura.
struct persona
{
	char nombre[20];
	int telefono;
} lista[10];

int main ()
{
	// asignacion de valores a la estructura
	strcpy(lista[1].nombre,"jose");
	lista[1].telefono = 12345678;
	strcpy(lista[2].nombre,"juan");
	lista[2].telefono = 34265891;
	strcpy(lista[3].nombre,"federico");
	lista[3].telefono = 64817592;
	strcpy(lista[4].nombre,"facundo");
	lista[4].telefono = 12363852;
	strcpy(lista[5].nombre,"asdfjklñ");
	lista[5].telefono = 58924719;
	strcpy(lista[6].nombre,"gabriel");
	lista[6].telefono = 52758195;
	strcpy(lista[7].nombre,"marcos");
	lista[7].telefono = 78298761;
	strcpy(lista[8].nombre,"pelotudo");
	lista[8].telefono = 42402098;
	strcpy(lista[9].nombre,"hola");
	lista[9].telefono = 39684489;
	strcpy(lista[10].nombre,"lalala");
	lista[10].telefono = 64573892;
	
	//declaración de variables
	char l;
	char name[20];
	int t;
	
	//impresión de menú
	cout << "Como quiere buscar a las personas?" << endl;
	cout << "a) Buscar por nombre." << endl;
	cout << "b) Buscar por numero de telefono." << endl;
	cout << "c) Salir del programa." << endl;
	cout << endl;
	
	//elección de opción
	
	cin >> l;
	
	if (l == 'a'){
		cout << "Introduzca el nombre:";
		cin >> name;
		buscarN(name);
	}
	else if(l == 'b'){
		cout << "Introduzca el telefono:";
		cin >> t;
		buscarT(t);
	}
	else if(l == 'c'){
		exit(0);
	}
	else
	{
		cout << "introduzca una de las opciones mencionadas" << endl;
	}
	
	return 0;
}

//definiciones de funciones
void buscarN(char name[20])
{
	//variables necesarias para la función
	bool verdad[10] = {false};
	int n;
	
	for (n = 1; n<=10; n++)
	{
		if (strcmp(name,lista[n].nombre) == 0)
		{
			cout << "el telefono de la persona es: " << lista[n].telefono;
		}
		else verdad[n] = true; //para verificar que el nombre de la persona no existe
	}
	
	if (verdad[1] == verdad[2]){
		if (verdad[2] == verdad[3]){
			if (verdad[3] == verdad[4]){
				if (verdad[4] == verdad[5]){
					if (verdad[5] == verdad[6]){
						if (verdad[6] == verdad[7]){
							if (verdad[7] == verdad[8]){
								if (verdad[8] == verdad[9]){
									if (verdad[9] == verdad[10]){
										if (verdad[10] == true){
											cout << "el nombre ingresado no existe.";
										}
									}
								}
							}
						}
					}
				}
			}
		}
	}
	
	exit(0);
}

void buscarT(int t)
{
	int n;
	bool verdad[10] = {false};
	
	for (n = 1; n<=10;n++)
	{
		if (t == lista[n].telefono)
		{
			cout << "el nombre de la persona es: " << lista[n].nombre;
		}
		else verdad[n] = true;
	}
	
	if (verdad[1] == verdad[2]){
		if (verdad[2] == verdad[3]){
			if (verdad[3] == verdad[4]){
				if (verdad[4] == verdad[5]){
					if (verdad[5] == verdad[6]){
						if (verdad[6] == verdad[7]){
							if (verdad[7] == verdad[8]){
								if (verdad[8] == verdad[9]){
									if (verdad[9] == verdad[10]){
										if (verdad[10] == true){
											cout << "el telefono ingresado no existe.";
										}
									}
								}
							}
						}
					}
				}
			}
		}
	}
	
	exit(0);
}


I feel like i'm kinda useless, i need help with almost everything. Does everyone need so much help?
Last edited on
long double main (999)
No, using std::string, you would just have to do
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#include <string>

struct persona
{
    std::string nombre; // Change this to std::string
    int telefono;
} lista[10];

int main()
{
    // asignacion de valores a la estructura
    lista[1].nombre = "jose"; // This works like you would expect -- no strcpy needed
    lista[1].telefono = 12345678;
    lista[2].nombre = "juan";
    lista[2].telefono = 34265891;
    // etc.
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