Convert a String to Float

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

int pow(int n, int i){
    if (i <= 0){
        return 1;
    }
    while(i-1){
        n = n * n;
        i--;
    }
    return n;
}

int custom_atoi(const char *str) {
    bool is_neg = false;
    int num_list[255];
    int size = 0;
    for (size_t i=0; i,255; i++){
        char chr = *(str+i);
        if (chr == '-' & i==0){
            is_neg = true;
        } else if  (chr == '+' & i==0){
            continue;
        } else if ((chr >= '0') & (chr <= '9')){
            int num = ((int)chr) - 48;
            num_list[size] = num;
            size++; 
        } else {
            break;
        }
    }

    int result = 0;
    for (size_t i=0; i<size; i++){
        int number = num_list[i] * pow(10, (size-i)-1);
        result += number;
    }
    if (is_neg) {
        result *= -1;
    }
    return result;
}

float custom_atof(const char *str) {
    char left[16] = "";
    char right[16] = "";
    bool is_neg = false;
    bool is_right = false;
    int dec = 0;

    for (size_t i=0; i<255; i++){
        char chr = *(str+i);
        if (chr == '\0'){
            break;
        }
        if (chr == '-'){
            is_neg = true;
            continue;
        }
        if (chr == '.'){
            is_right = true;
            continue;
        }

        int num = (int)(chr-'0');
        if (is_right){
            sprintf(right, "%s%c", right, chr);
            dec++;
        } else {
            sprintf(left, "%s%c", left, chr);
        }
    }
    int num_left = custom_atoi(left);
    float num_right = (float)custom_atoi(right) / (float)pow(10, dec);
    float result = num_left + num_right;
    if (is_neg) {
        result *= -1;
    }
    return 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;
}