Convert a String to Float

Code

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

float custom_atof(const char *str) {
    float res; 
    float res_int = 0.0f; 
    float res_frac = 0.0f;
    float sign = 1.0f; 
    float divisor = 10.0f;
    int i = 0;
    int seen_decimal = 0; 

    if (str[0] == '-')
    {  
        sign = -1.0f; 
        i++; 
    }
    else if (str[0] == '+')
    {
        i++; 
    }

    while (str[i] != '\0')
    {
        if (seen_decimal == 0 && str[i] == '.')
        {
            seen_decimal = 1; 
            i++;
            continue;
        }

        if (seen_decimal)
        {
            res_frac += (str[i] - '0') / divisor; 
            divisor *= 10.0f;
        }
        else
        {
            res_int = res_int * 10.0f + (str[i] - '0'); 
        }

        i++; 
    }

    res = sign * (res_int + res_frac);

    return res;
}

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;
}

Solving Approach