Convert a String to Float

Code

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


#include <stdbool.h>

float custom_atof(const char *str)
{
    bool negative = false;
    float result = 0.0f;
    float fraction = 0.0f;
    float divisor = 1.0f;

    // Handle sign
    if (*str == '-') {
        negative = true;
        str++;
    }

    // Integer part
    while (*str && *str != '.') {
        if (*str >= '0' && *str <= '9') {
            result = result * 10.0f + (*str - '0');
        }
        str++;
    }

    // Fractional part
    if (*str == '.') {
        str++;
        while (*str && *str >= '0' && *str <= '9') {
            fraction = fraction * 10.0f + (*str - '0');
            divisor *= 10.0f;
            str++;
        }
        result += fraction / divisor;
    }

    return negative ? -result : result;
}

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