At the beginning of a program I need to dynamically allocate memory for an unknown number of strings with unknown number of size to later manipulate with. To get the number of strings from a user I have:
int main(int argc, char *argv[]){
int number = atoi(argv[1]);
So far so good. "number" now holds holds the number that the user inputted on the command line for executing the code. Now here comes the part I don't quite understand. I now need to dynamically store the lengths of the strings as well as the contents of the strings. For example, I want the program to function like this:
Enter the length of string 1: 5
Please enter string 1: hello
Enter the length of string 2: ...
For this I recognize that I will have to create an array of strings. However, I can't quite understand the concept of pointers to pointers and what not. What I would like is perhaps a simplification of how this gets accomplished?
You know from the start you will have number strings to store so you will need an array of size number to store a pointer to each string.
You can use malloc to dynamically allocate enough memory for number char pointers:
char** strings = malloc(number * sizeof(char*));
Now you can loop number times and allocate each string dynamically:
for (int i = 0; i < number; i++) {
// Get length of string
printf("Enter the length of string %d: ", i);
int length = 0;
scanf("%d", &length);
// Clear stdin for next input
int c = getchar(); while (c != '\n' && c != EOF) c = getchar();
// Allocate "length" characters and read in string
printf("Please enter string %d: ", i);
strings[i] = malloc(length * sizeof(char));
fgets(strings[i], length, stdin);
}
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