98. Convert String to Integer

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

int custom_atoi(const char *str) {
    int i = 0;
    int sign=1;
    long res = 0;
    if (str[i]=='-'){
        sign = -1;
        i++;
    }
    else if (str[i]=='+') {
        i++;
    }
    while (str[i]>='0' && str[i]<='9') {
        int digit = str[i] - '0';
        res = (res*10) + digit;
        i++;
    }
    return (int) (res*sign);
}

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;
}