#include <stdio.h>
#include <stdlib.h>
#include <string.h>
unsigned int my_strlen(const char tab[]) {
  int i = 0;
  if (tab[0] == '\0')
      return 0;
  else
    while(tab[i] != '\0')
        i = i + 1;

  return i;
}

int my_atoi(const char tab[])  {
    int value = 0, i = 0, sign = 1;
    if(tab[0] == '-') {
        i=1;
        sign = -1;
    } else if(tab[0] == '+')
        i=1;
    while (tab[i] >= '0' && tab[i] <= '9')
        value = value*10 + tab[i++]-'0';

    return value * sign;
}

float my_atof(const char tab[]) {
    double value, power;
    int i = 0, sign = 1;
    if(tab[0] == '-') {
        i=1;
        sign = -1;
    } else if(tab[0] == '+')
        i=1;
    for (value = 0.0; tab[i] >= '0' && tab[i] <= '9'; i++)
        value = 10.0 * value + (tab[i] - '0');
    if (tab[i] == '.')
        i++;
    for (power = 1.0; tab[i] >= '0' && tab[i] <= '9'; i++) {
        value = 10.0 * value + (tab[i] - '0');
        power *= 10.0;
    }

    return sign * value / power;
}

int main(void) {
    char tab[15] = "";
    printf("Podaj liczbę: ");
    fgets(tab, 16, stdin);
    printf("%d\n", my_strlen(tab));
    printf("%d\n", my_atoi(tab));
    printf("%.4f\n", my_atof(tab));
    printf("%ld\n", strlen(tab));
    return 0;
}