Learn how to Convert Strings to Integers in C

C is a powerful language and learning how to switch between types like strings and integers is a crucial skill to have.

In this post, we'll learn how you can convert a string to an integer in C.

Converting a string to an integer

The best way to convert a string to an integer in C is by using the atoi() function.

This function comes with the standard library, stdlib.h, and is used to convert a string to an integer.

To use the function, you need to include the header file stdlib.h in your program.

From there, simply call the function atoi() and pass it the string you want to convert.

Let's look at an example:

	#include <stdio.h>
#include <stdlib.h>

int main() {
    char *string = "123";

    int integer = atoi(string);

    printf("%d", integer);

    return 0;
}

It's that simple. When you run this C code, the output will be 123.

Keep in mind that if you pass in a string that is not a number, the function will return 0. However, if the string starts with a number, it will parse the string until it reaches a non-numeric character.

Here's an example of a string that is not a full number:

	#include <stdio.h>
#include <stdlib.h>

int main() {
    char *string = "123abc";

    int integer = atoi(string);

    printf("%d", integer);

    return 0;
}

This will return 123, because so long as the string starts with a valid number, you can use this function to convert a string to an integer.