Scanf parsing string input into array of chars

Question

I want to parse a user-input (using scanf) in 2 separate arrays. g++ compiles without error, but I get a memory-access-error (core dumped). (in german: \"Speicherzugriffsfehler

Answer 1

As another answer says, you have to allocate place for your strings. You want an array of top and bottom strings, but with char * top[10] you are only allocating room for 10 pointers, not for the characters in the strings. The reason why top[10] = "Hello" works is that string literals are implicitly allocated by the compiler, which returns a pointer to those characters.

char *top[10], *bottom[10];
for(i = 0; i < 5; i++)
{
    top[i] = malloc(100); // reserve room for string up to 100 chars
    printf("Karte %d: Obere Werte? ", i);
    scanf("%s",top[i]);
    bottom[i] = malloc(100);
    printf("Karte %d: Untere Werte? ", i);
    scanf("%s",bottom[i]);
}