bug2new.c

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

/* This program is supposed to test if you get the same random numbers
   if you reset the random number generator with a certain seed
   value. */
int main(void){

    int i, j, seed, failed, tested;
    int **mybuffer;

    printf("Please enter a seed for the random number generator (any integer): ");
    scanf("%d",&seed);
    srand(seed);

    /* Allocate a bunch of pointers */
    mybuffer = calloc(100,sizeof(int *));
    if (mybuffer == NULL){
        fprintf(stderr, "Failed to allocate memory!");
        exit (-1);
    }
    /* Allocate memory to each pointer */
    for (i=0 ; i<100 ; i++){
        mybuffer[i] = calloc(10,sizeof(int));
        if (mybuffer[i] == NULL){
            fprintf(stderr, "Failed to allocate memory!");
            exit (-1);
        }
    }
    /* Fill the allocated memory with random numbers */
    for (i=0 ; i<100 ; i++){
        for (j=0 ; j<10 ; j++){
            mybuffer[i][j] = rand();
        }
    }

    /* Lets try to see if we get the same random numbers again. */
    /* Reset the seed to the random number generator. */
    srand(seed);
    failed = 0;
    tested = 0;
    for (i=0 ; i<100 ; i++) {
        for (j = 0; j < 10; j++) {
            if (mybuffer[i][j] != rand()) {
                printf("Random number mismatch!\n");
                failed = 1;
            }
            tested++;
        }
    }

    if (failed)
        printf("Something went wrong...\n");
    else
        printf("%d number verified and correct\n",tested);

    /* Release the memory */
    for (i=0 ; i<100; i++){
        free(mybuffer[i]);
    }
    free(mybuffer);
    return 1;
}