Convert String to Integer

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

int custom_atoi(const char *str) {
    // Your logic here
    char res[101];
    int i=0,j=0,num=0,sign=1;
    while(str[i]!='\0'){
        if(i==0 && (str[i]=='+' || str[i]=='-')) {
            if( (str[i])== '+') sign=1;
            else sign=-1;
        }
        if(str[i]>='0' && str[i]<='9'){
          
          num=(num*10)+(str[i] - '0');

        }
        else if((str[i]=='+' || str[i]=='-')){
             i++;
             continue;}
        else {
             break;
        }
        
      i++; 
    }
  return (num*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;
}