Convert String to Integer

#include <stdio.h>
#include <stdint.h>
int custom_atoi(const char *str) {
    int i=0;
    int neg=1;
    int num=0;
    if(str[i]=='-')
    {
        neg=-1;
        i++;
    }
    else if(str[i]=='+')
        i++;
    int o=0;
    while(str[i]!='\0'){
        if(str[i]>='0' && str[i]<='9'){
           o=1;
           num=(num*10)+(str[i]-'0');
        }
        else{
            num = neg*num;
            return num;
        }
        i++;
    }
    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;
}