C ++, how to fill 5 elements int vector with function

Advice: Learn to indent properly your code, it show its structure and it helps reading and understanding. It also helps spotting structures mistakes.

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;

int  CarteACaso () {
	int NumeroCarte;
	srand((int)time(0));
	NumeroCarte= (rand() % 4) + 1;
	return NumeroCarte;
}

int main() {
	int gioco[5];
	for(int P=0; P<5; P++) {
		int Prova;
		Prova=CarteACaso();
		gioco[P]=Prova;
		cout<<"gioco  "<<P<<"  "<<gioco[P]<<endl;
	}
	return 0;
}

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As mentioned, the srand call needs to moved out of that function and into main so it is called once.

You also have a problem with how you are using the return from rand(). You stated you want random values between 0 and 4. The function returns random values from 0 to RAND_MAX with is typically 32K. You are adding one to the result of the return modulo 4. This means the values will range from 1 to 4. Here is a function that will return values within the range specified.

int GetRandomValue( int minval, int maxval )
{
    int range = maxval - minval + 1;
    int rval = rand() % range;
    return rval + minval;
}

You want numbers that range from 0 to 4 so call this function and pass the values 0 and 4 to it.

Here's code that will test of that function :

void DoRandomValueTest()
{
    std::vector< int > values( 10, 0 );
    const int count = 1000;
    for( int n = 0; n < count; ++n )
    {
        int rv = GetRandomValue( 1, 8 );
        values[ rv ] += 1;
    }

    size_t valueCount = values.size();
    trace( _T( "random value vector has %d items\n" ), (int) valueCount );
    for( size_t i = 0; i < valueCount; ++i )
        trace( _T( "%2d : %4d times\n" ), (int) i, values[ i ] );
}

Here is the output from the test :

21:04:02.279 TestThread_07   random value vector has 10 items 
21:04:02.279 TestThread_07    0 :    0 times 
21:04:02.279 TestThread_07    1 :  129 times 
21:04:02.279 TestThread_07    2 :  143 times 
21:04:02.279 TestThread_07    3 :  116 times 
21:04:02.279 TestThread_07    4 :  113 times 
21:04:02.279 TestThread_07    5 :  119 times 
21:04:02.279 TestThread_07    6 :  135 times 
21:04:02.279 TestThread_07    7 :  129 times 
21:04:02.279 TestThread_07    8 :  116 times 
21:04:02.279 TestThread_07    9 :    0 times

As you can see, all values are within the range of 1 to 8. The distribution is reasonably flat for such a small range.

hello guys thanks for your valuable tips.
about indentation, i have been reading the links but i got lost, there are lot of styles.
i ll try to use the one you suggested in the post. i am using dev c++.
as you realized, i am a beginner.
i am very happy having known this site. it's vital for my learning. likely i ll submit bunch of questions, this the only way i have to learn. thank you again.