Convert a String to Float

Code

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

float custom_atof(const char *str) {
    float result = 0.0f;
    float fraction = 0.0f;
    int sign = 1;
    int i = 0;
    int after_dot = 0;

    if (str[i] == '-') 
    {
        sign = -1;
        i++;
    } 
    else if (str[i] == '+') 
    {
        i++;
    }

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

        if (str[i] >= '0' && str[i] <= '9') 
        {
            if (!after_dot) 
            {
                result = result * 10.0f + (str[i] - '0');
            }
            else 
            {
                fraction = fraction * 10.0f + (str[i] - '0');
                after_dot *= 10;
            }
        }
        i++;
    }

    if (after_dot > 1) 
    {
        result += fraction / after_dot;
    }

    return result * 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++;
    }

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

Solving Approach