Convert a String to Float

Code

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

float custom_atof(const char *str) {
    int sign;
    int i;
    float sum;

    sign = 0;
    i = 0;
    sum = 0.0;
    
    if(str[i] == '+')
    {
        sign = 1;
        i++;
    }
    else if(str[i] == '-')
    {
        sign = -1;
        i++;
    }

    while(str[i])
    {
        if(str[i] == '.')
        {
            i++;
            break;
        }
        sum = sum * 10 + str[i] - '0';
        i++;
    }

    float divisor = 10.0;
    while(str[i])
    {
        sum += (str[i] - '0') / divisor;
        divisor *= 10;
        i++;
    }

    if(sign == -1)
        sum *= sign;
    return sum;
}

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