Convert a String to Float

Code

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

float custom_atof(const char *str) {
    float res = 0.0f;
    float frac = 0.0f;
    float div = 1.0f;
    int sign = 1;

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

    while(*str != '\0' && *str != '.'){
        res = res * 10.0f + (*str - '0');
        str++;
    }

    if(*str == '.'){
        str++;
        while(*str != '\0'){
            frac = frac * 10.0f + (*str - '0');
            div *= 10.0f;
            str++;
        }
    }

    return sign * (res + (frac/div));
}

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