BigSum

#include<stdio.h>
#include<string.h>

int chrtoint(char a){
int i;
for (i = 48; i<=57; i++)
if (toascii(i)==a) return i-48;
return 0;
}

void main(){
char n1[1000];
char n2[1000];
int rs[1001];
int c1, c2;
int i,j,m=0, cmax, sum;

scanf("%s", n1);
scanf("%s", n2);
c1 = strlen(n1);
c2 = strlen(n2);
strrev(n1);
strrev(n2);

cmax = c1;
if(c1<c2){
cmax = c2;
}

for(i=0; i< cmax; i++){
if(c1==c2 || (i < c1 && i < c2)){
sum = m+chrtoint(n1[i])+chrtoint(n2[i]);
}
else if(i >=c1){
sum = m+chrtoint(n2[i]);
}else if(i >=c2){
sum = m+chrtoint(n1[i]);
}
rs[i] = sum%10;
m = sum/10;
}

if(m){
rs[i]=m;
i++;
}

for(j=0; j < i; j++){
printf("%d", rs[i-j-1]);
}

}