如何使用数字 1、2、3、4 生成随机 5 位数字并将这些生成的数字存储在 C 语言的数组中

Question

I have to generate the random 5 digit number using 1,2,3,4 numbers and store generated numbers in array

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

// Generates and prints 'count' random
// numbers in range [lower, upper].
void printRandoms(int lower, int upper, int count)
{
    int i;
    char str[45];
    char k[45];

    for (i = 0; i < count; i++)
    {
        int num = (rand() % (upper - lower + 1)) + lower;

        sprintf(str, "%d", num);
        strcat(str, k);
        printf("%d ", num);
    }

    printf("%d", k);
}

// Driver code
int main()
{
    int lower = 1, upper = 5, count = 5;

    // Use current time as
    // seed for random generator
    srand(time(0));

    printRandoms(lower, upper, count);

    return 0;
}

Expected Output:

[11111, 12343, 12123, 12121, 12323, 44444]

Answer 1

You made 3 mistakes in your program:

1. With the function strcat , the first parameter is the destination string and the second parameter is the source string. In your function call to strcat , you must therefore swap these two parameters.

2. In contrast to strcpy , when using strcat , both parameters must be initialized strings, since you are appending one string to another string. If you want the string (char array) k to be empty at the start and add a digit to it once per loop, you must initialize it to an empty string before the loop, for example by writing strcpy( k, "" ); or k[0] = '\0';

3. The line printf("%d",k); is wrong. In order to print a string with printf, you must use %s instead of %d .