rand() 为我的 while 循环输出相同的数字但不是我的 for 循环

Question

I am making this code for a random dice roller and I want to get a random number until I get three 6's on the dice. For some reason this produces the same number for all runs, but on my for loop it works. Can I get some help getting this to work?

The pesky While loop in question:

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

int Ran(int max) {
return (rand() % max)+ 1;
}

int main(){

    int max = 6;
    int nsuc = 0, ncount = 0;
    int matt = 40;
    srand((unsigned) time(0));

    for(int i = 1; i <= 20; i++){
        while(!(nsuc >= 3)){
            int nr = Ran(max);
            if(nr < matt){
                ncount++;
                if(nr == 6){
                    nsuc++;
                }
            }
        }
        printf("Number of rolls until 3 6's = %d\n", ncount);
    }
}

Cleaned up the for loop so it's easier to read now:

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


void Shuffle() {
srand((unsigned) time(NULL));
}

int Ran(int max) {
return (rand() % max)+ 1;
}

void binomial(int run, int max, int btrials, int *array, int scount){

    for(int j = 1; j<=run; j++){
        for (int i=1;i<=btrials;i++){
            int r = Ran(max);
            if(r == 6){
            scount++;
            }
        printf("Trial %i, roll = %d\n",i , r);
        }
        array[j-1] = scount;
        scount = 0;
        printf("\nEnd of Run %d\n\n",j);
    }

}

int main(){

    int Runs;
    printf("How many runs do you want to do? > ");
    scanf("%d", &Runs);
    printf("\n");

    int bdist[20];
    int distcount = 0;
    int max = 6;
    int btrials = 20;
    int suc[Runs+1];
    int scount = 0;



    Shuffle();
    binomial(Runs, max, btrials, suc, scount);

    printf("All counts of succesful 6 rolls.\n");

    /*
    for(int z = 1; z<=Runs; z++){
        printf("Run %d has %d 6's\n", z, suc[z-1]);
    }
    */

    for(int k = 0; k<=btrials; k++){
        for(int j = 1; j<=Runs; j++){
            if(suc[j-1] == k){
                distcount++;
            }     
        }
        bdist[k] = distcount;
        distcount = 0;
    }

    for(int t = 0; t<=btrials; t++){
        printf("Number of runs with %d 6s = %d\n", t, bdist[t]);
    }

    return 0;

}

Answer 1

You never reset nsuc or ncount in the first version with the while loop. After the first time thru, they still have their values from the previous loop so you get the same output.

Answer 2

Not an answer strictly related to the question, but something I noticed.

If I recall, generating ranged random numbers using the (rand % max)+ 1 idiom is not advised.

One .

Two