A1001 A+B Format

#include<cstdio>
#include<cstring>

int num[10];

int main(){

    int a,b;
    scanf("%d %d",&a,&b);

    int sum = a+b;

    if(sum<0){
        printf("-");
        sum = -sum;
    }

    int len=0;
    if(sum==0)    num[len++] = 0;

    do{
        num[len++] = sum%10;
        sum /= 10;
    }while(sum!=0);

    for(int k=len-1;k>=0;k--){
        printf("%d",num[k]);
        if(k>0 && k%3==0)    printf(",");
    }


    return 0;
}

#include<cstdio>
#include<cstring>



int main(){

    int a,b,sum;
    scanf("%d %d",&a,&b);

    sum = a+b;

    if(sum<0){
        printf("-");
        sum = -sum;
    }

    if(sum>=1000000)    printf("%d,%03d,%03d",sum/1000000,sum%1000000/1000,sum%1000);
    else if(sum>=1000)    printf("%d,%03d",sum/1000,sum%1000);
    else printf("%d",sum);



    return 0;
}