Convert a String to Float

Code

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

float custom_atof(const char *str) {
    int i=0;
    float fn=0.0f;
    float fraction=0.0f;
    float divisor=10.0f;
    int sign=1;
    int fract=0;
    if(str[i]=='-'){
        sign=-1;
        i++;
    }
    else if(str[i]=='+'){
        sign=1;
        i++;
    }
    while(str[i] != '\0'){
        if(str[i] =='.'){
            fract=1;
            i++;
        }
        if(str[i] >= '0' && str[i] <= '9'){
            if(!fract){
                fn=fn*10.0f + (str[i]-'0');
            }
            else{
                fraction += (str[i]-'0')/divisor;
                divisor *=10.0f;
            }
        }
        else{
            break;
        }
        i++;
    }
    return sign * (fn+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