98. Convert String to Integer

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

int custom_atoi(const char *str) {
    if(str == NULL) return 0;
    if(*str == '0') {
        return 0;
    }
    int sign = 0;
    bool has_sign = false;
    if(*str == '-') {
        sign = -1;
        str++;
        has_sign = true;
    } else if (*str == '+'){     
        str++;
    }
    int num = 0;
    while(*str) {
        if(*str >= '0' && *str <= '9') {
            num = num * 10 + (*str - '0');
        } else{
           break;
        }
        str++;
    }
    if(has_sign) {
        num = -num;
    }
    return num;
}

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;
}