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 decimal_found = 0;
    float decimal_scale = 0.1f;

    if(*str == '-'){
        sign = -1;
        str++;
    }else if(*str == '+'){
        str++;
    }

    while(*str != '\0'){
        if(*str >= '0' && *str <= '9'){
            if(!decimal_found){
                result = result * 10 + (*str - '0');
            }else{
                fraction += (*str - '0') * decimal_scale;
                decimal_scale *= 0.1f;
            }
        }else if(*str == '.'){
            decimal_found = true;
        }else{
            break;
        }
        str++;
    }
    return sign * (result + 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;
}

Solving Approach