Thread: srand problems

Hello,

How do i make the srand() function make new numbers every time i call it? Now it seems like it repeats its result over an over again.

Below is a program that should generate random numbers for 3 dices and print these out. But it prints out the same nr over and over.

Code:

#include <stdio.h>


#define MAX 100


int filler(int dice1[MAX], int dice2[MAX], int dice3[MAX])
{
    int throws, nr;
    printf("Define the number of throws");
    scanf("%d", &kast);


    int i;
    for(i = 0; i <= throws; i++)
    {
        nr = rand()%6;
        dice1[i] = nr;
        nr = rand()%6;
        dice2[i] = nr;
        nr = rand()%6;
        dice3[i] = nr;
    }


    int j;
    for(j = 0; j <= throws; j++)
    {


        printf("%d\n", dice1[j]);


        printf("%d\n", dice1[j]);


        printf("%d\n", dice1[j]);
    }
}






int main(void)
{
    srand(time(NULL));


    int dice1[MAX];
    int dice2[MAX];
    int dice3[MAX];
    filler(dice1, dice2, dice3);
}

You're only printing the values in dice1.

Thank you! i added <stdlib.h>, <time.h> and made the code print dice2 and dice3 swell and now it works perfectly

I have got some more problems with the code. This program ask the user to specify the nr of throws then it throws 3 dices and add these 3 dices to sum.

Then another function sorts the sum form the smallest to the largest with a bubble sorting algorithm.

the first two functions seems to work but the program does not print out the result of the 3rd sorting function.

Code:

#include <stdio.h>
#include <stdlib.h>
#include <time.h>


#define MAX 100

//This function ask the user for the amout of throws
int numberofthrows() 
{
    int throws;
    printf("Type in the number of throws");
    scanf("%d", &throws);
    return throws;
}

//This function makes the random throws of 3 dices with regard to the number of throws

int filler(int thrownr, int dice1[MAX], int dice2[MAX], int dice3[MAX], int sum[MAX])
{
    int i, nr;
    srand(time(NULL));
    for(i = 0; i <= thrownr; i++)
    {


        nr = rand()%6;
        dice1[i] = nr + 1;


        nr = rand()%6;
        dice2[i] = nr + 1;


        nr = rand()%6;
        dice3[i] = nr + 1;


        sum[i] = dice1[i] + dice2[i] + dice3[i];




    }


    int j;
    for(j = 0; j <= thrownr; j++)
    {




        printf("%d ", dice1[j]);


        printf("%d ", dice2[j]);


        printf("%d ", dice3[j]);


        printf("%d\n", sum[j]);
    }
}

//This function sorts the result in form the sum array

int sorter(int thrownr, int sum[MAX], int sortsum[MAX])
{
    int tmp, i, j, k, m;




    for(i = 0; i <= thrownr; i++)
    {
        sortsum[i] = sum[i];
    }


    for(m = 0; m <= 10; m++)
    {
        for(j = 0; j <= thrownr; i++)
        {


            if (sortsum[j] > sortsum[j+1])
            {
                tmp = sortsum[j];
                sortsum[j] = sortsum[j+1];
                sortsum[j+1] = tmp;
            }




        }


    }


    for(k = 0; k <= thrownr; k++)
    {
        printf("%d\n", sortsum[k]);
        printf("%d\n", sum[k]);
    }




}








int main(void)
{
    srand(time(NULL));
    int dice1[MAX];
    int dice2[MAX];
    int dice3[MAX];
    int sum[MAX];
    int sortsum[MAX];


    int numberofthrows2;


    numberofthrows2 = numberofthrows();


    filler(numberofthrows2, dice1, dice2, dice3, sum);


    sorter(numberofthrows2, sum, sortsum);


    return 0;
}