How do you cast a char* to an int or a double in C [closed]

Question

Sorry if this is a super easy question, but I am very new to C. I want to be able to cast char*s into doubles and ints and can't seem to find an explanation as to how.

Edit: I am reading in user input, which is a char*. Half of the input I want to convert from, say, "23" to 23 and half from, for example, "23.4" to 23.4.

Answer 1

You can cast a char* like this:

char  *c = "123.45";
int    i = (int) c;      // cast to int
double d = (double) c;   // cast to double

But that will give nonsensical results. It just coerces the pointer to be treated as an integer or double.

I presume what you want is to parse (rather than cast) the text into an int or double. Try this:

char  *c = "123.45";
int    i = atoi(c);
double d = atof(c);

Answer 2

Strictly speaking, you can do this: (int)pointer.

However, you are probably looking for the atoi and atof functions.

atoi is a function that converts a char* pointing to a string containing an integer in decimal to an integer .

atof is likewise for double.