大数加法

大数加法/C语言源程序

#include<bits/stdc++.h>
#include<iostream>
using namespace std;

int main()
{
    char a[1000],b[1000],c[1000];
    int m,n1,n2,k=0;//k是进位；m是各位相加结果；
    int i=0;
    scanf("%s%s",a,b);
//  getchar();
    n1=strlen(a);
    n2=strlen(b);
    reverse(a,a+n1);
    reverse(b,b+n2);
    while(a[i]&&b[i])
    {
        m=(a[i]-'0')+(b[i]-'0')+k;
        k=m/10;
        c[i]=(m%10+'0');
        i++;
    }
    if(i==n1)
    {
        while(i!=n2)
        {
            m=(b[i]-'0')+k;
            k=m/10;
            c[i]=m%10+'0';
            i++;
        }
        if(k)
            c[i]=k+'0';
    }
    else if(i==n2)
    {
        while(i!=n1)
        {
            m=(a[i]-'0')+k;
            k=m/10;
            c[i]=m%10+'0';
            i++;
        }
        if(k)
            c[i]=k+'0';
    }
    reverse(c,c+i);
    for(int j=0;j<i;j++)
      printf("%c",c[j]);
    printf("n");
    return 0;
}

C++ 程序

string add(string a,string b)
{
    string ans;

    reverse(a.begin(),a.end());
    reverse(b.begin(),b.end());
    int m=0,carry=0,i=0;
    while(a[i]&&b[i])
    {
        m=a[i]-'0'+b[i]-'0'+carry;
        carry=m/10;
        ans+=m%10+'0';
        i++;
    }
    if(i==a.size())
    {
        while(i!=b.size())
        {
            m=b[i]-'0'+carry;
            carry=m/10;
            ans+=m%10+'0';
            i++;
        }
        if(carry)
            ans+=carry+'0';
    }
    else if(i==b.size())
    {
        while(i!=a.size())
        {
            m=a[i]-'0'+carry;
            carry=m/10;
            ans+=m%10+'0';
            i++;
        }
        if(carry)
            ans+=carry+'0';
    }
    reverse(ans.begin(),ans.end());
    return ans;
}