c - Why the for loop is filling the whole array with the latest string?

Question

Apologies if this is simple, but I am new to C. I am trying to create a loop that fills in an empty array of strings with multiple strings. However, at the end, the whole array is being filled with the latest element ! Below is the code:

int main(void)
{
    string array_test[2];
    char string_test[300];

    for (int i = 0; i < 2; i++)
    {
        snprintf(string_test, sizeof(string_test),"Test: %i", i);
        array_test[i] = string_test;
    }

    for (int i = 0; i < 2; i++)
    {
        printf("%s
", array_test[i]);
    }
}

This returns:

Test: 1
Test: 1

But I am expecting:

Test: 0
Test: 1

Answer 1

Because you are using the same buffer to save strings in all iterations. This will make previous strings overwritten by new strings.

Allocate separate buffers for each strings to avoid this.

/* put #include of required headers here */

int main(void)
{
    string array_test[2];
    char string_test[2][300];

    for (int i = 0; i < 2; i++)
    {
        snprintf(string_test[i], sizeof(string_test[i]),"Test: %i", i);
        array_test[i] = string_test[i];
    }

    for (int i = 0; i < 2; i++)
    {
        printf("%s
", array_test[i]);
    }
}