#include <iostream>
#include <string.h>

int strToInt(char *s)
{
    int tmp = 0, minus = 0;

    if (*s == '-') {
        minus = 1;
        *s++;
    }

    while(*s)
        tmp = 10 * tmp + *s++ - 48;

    return minus ? -tmp : tmp;
}


char *intToStr(int n)
{
    int i = 0, g = 0, minus = 0;
    char *tmp = (char*)malloc(sizeof(char)), *rev = (char*)malloc(sizeof(char));

    if (n < 0) {
        minus = 1;
        n = abs(n);
    }

    do {
        tmp[i] = n % 10 + 48;
        n -= n % 10;

        i++;
    }while(n /= 10);

    if(minus) {
        tmp[i++] = '-';
    }

    for(i--; i >= 0; i--) {
        rev[i] = tmp[g++];
    }

    return rev;
}

int main () {

    printf("%d", strToInt(intToStr(-15)));

    getchar();
    return 0;
}