大数加法

1.加法

//A+B问题
#define _CRT_SECURE_NO_DEPRECATE
#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
char s1[1000], s2[1000];
void add()
{
    char s3[1000];
    int len1 = strlen(s1),len2 = strlen(s2),len;
    if (len1<len2)    len = len2;
    else len = len1;
    int i = len1 - 1, j = len2 - 1, h = 0,loc = 0,x=0;
    s1[len1] = '0',s2[len2] = '0';
    while (len--)
    {
        s3[h] = ((s1[i] - '0') + (s2[j] - '0') + loc) % 10 + '0';
        x = s3[h]-'0';
        loc = ((s1[i] - '0') + (s2[j] - '0')+loc) / 10;
        if (i>0 && j>0 && j != len2 && i != len1)
        {
            i--, j--,h++;
        }
        else if (i <= 0 || i == len1)
        {
            j--,i = len1,h++;
        }
        else if (j <= 0 || j == len2)
        {
            i--, j = len2,h++;
        }
        else
            break;
    }
    if(loc)
        s3[h++] = loc + '0';
    for (int i = h - 1; i >= 0; i--)
        printf("%c", s3[i]);
}
int main()
{
    int cas;
    cin>>cas;
    for(int i=1;i<=cas;i++)
    {
    scanf("%s", s1);
    scanf("%s", s2);
    printf("Case %d:\n%s + %s = ",i,s1,s2);
    add();
    cout<<endl;
    if(i!=cas)
    cout<<endl;
    }
    return 0;
}

 1加法（简单版）

#include<stdio.h>
#include<string.h>
#define MAX 1000                  /*宏定义，下面遇到MAX的时候都变成1000 */
int main(void)
{
    unsigned  char  arr1[MAX]={0},arr2[MAX]={0};
    int len,i,len1,len2,t,j = 0;
    char str[MAX];               /*读入数据，并进行预处理(计算出数字位数，并反方向存放)*/
    scanf("%s",str);
    len1 = strlen(str);
    for(i=0; i<len1; ++i)
        arr1[i] = str[len1-1-i] - '0';
    scanf("%s",str);
    len2 = strlen(str);
    for(i=0; i<len2; i++)
        arr2[i] = str[len2-1-i] - '0';
    len = (len1>len2)?len1:len2;
    for(i=0; i<len; i++)
    {
        t = arr1[i] + arr2[i] +j;
        arr1[i] = t % 10;
        j = t / 10;
    }
    if(j != 0) arr1[len++] = j;
    for(i=0; i<len; ++i)
        printf("%d",arr1[len-1-i]);   
    return 0;
}