#include <stdio.h>
#include <stdlib.h>
#include <time.h>

typedef char ent30[31];

void aleat30(ent30 z);
void sumarn30(ent30 a,ent30 b,ent30 suma,int *acarreo);

int main(void)
{
  ent30 a,b,suma;
  int acarreo;

  srand(time(0));
  aleat30(a);
  aleat30(b);

  sumarn30(a,b,suma,&acarreo);

  printf("   a = %31s\n   b = %31s\nsuma = %d%30s\n",a,b,acarreo,suma);
  return 0;
}

void aleat30(ent30 z)
{
  int i;
  for(i=0;i<30;i++)
  {
    z[i]='0'+rand()%10;
  }
  z[30]='\0';
}

#define CharADig(c) ((int)((c)-'0'))
#define DigAChar(d) ((char)(d)+'0')

void sumarn30(ent30 a,ent30 b,ent30 suma,int *ua)
{
  int i,ap=0;
  suma[30]='\0';
  for(i=29;i>=0;i--)
  {
    const int sumadig=CharADig(a[i])+CharADig(b[i])+ap;
    suma[i]=DigAChar(sumadig%10);
    ap=sumadig/10;
  }
  *ua=ap;
}