Question

How to generate N random numbers that include specific digit X times in C

Answer 1

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

void generate_numbers_that_include_specific_digit_x_times(int N, int xtims, int digit, int rndtimes, int to) {
    srand(time(NULL));
    
    int total_numbers = 0;
     
    for (int i = 1; i <= rndtimes; i++) {
        int n = rand() % to + 1;
        int copy_n = n;
        int count = 0;
        
        if (N == total_numbers) {
            return;
        }
        
        while (n > 0) {
            if (n % 10 == digit)
                count++;
            n = n / 10;
        }
        
        if (count == xtims) {
            total_numbers++;
            printf("%d\n", copy_n);
        }
    }
}

int main(void)
{
    generate_numbers_that_include_specific_digit_x_times(5, 3, 7, 2000, 1000000);

    return 0;
}
 
 
 
/*
run:
 
776367
995777
752177
727472
775970
 
*/

 

70+ SQL courses for beginners and professionals