100. Convert a String to Float

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

float custom_atof(const char *str) {
    int sign=1;
    float res=0.0f;
    float divisor =10.0f;
    float fraction=0.0f;
    uint8_t in_fa=0;
    uint8_t i=0;
    if(str[i]=='-'){
        sign=-1;
        i++;
    }else if(str[i]=='+'){
        i++;
    }
    while(str[i]!='\0'){
        if(str[i]=='.'){
            in_fa=1;
            i++;
         continue;
        }
        if(str[i]>='0'&&str[i]<='9'){
            int digit =str[i]-'0';
            if(!in_fa){
                res=res*10.0f + digit;
            }else{
                fraction+=digit/divisor;
                divisor*=10.0f;
            }
        }else{
            break;
        }
        i++;
    }
   return sign*(res+fraction);
}

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++;
    }

    float value = custom_atof(str);
    printf("%.2f", value);
    return 0;
}