Convert String to Integer

Code

#include <stdio.h>
#include <stdint.h>

int custom_atoi(const char *str) {
    int head = 0;
    int num = 0; 
    int mul = 1;

    if (str[head] == '-' || str[head] == '+') {
        mul = (str[head] == '-') ? -1 : 1;
        head++;
    }


  for (; str[head] >= '0' && str[head] <= '9'; head++) {
        num = num * 10 + (str[head] - '0');
    }

    return num*mul;
}

int main() {
    char str[101];
    fgets(str, sizeof(str), stdin);

    // Remove newline
    uint8_t i = 0;
    while (str[i]) {
        if (str[i] == '\n') {
            str[i] = '\0';
            break;
        }
        i++;
    }

    printf("%d", custom_atoi(str));
    return 0;
}

Solving Approach