Convert String to Integer

Code

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

int custom_atoi(const char *str) {
    uint8_t is_negative = *str == '-';

    // sign in front just move to next char
    str += is_negative || *str == '+';
    
    int result = 0;

    while (*str >= '0' && *str <= '9') {
        result = result * 10 + (*str - '0');
        ++str;
    }

    if (is_negative) {
        return -result;
    }

    return result;
}

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