要机试了,练了几道题。贴一下大数相乘的写法,关键是加法:
#include<iostream> #include<string> using namespace std; #define Max 100 void Add(char*cA,int nNum) { nNum=nNum+*cA-'0'; int high=nNum/10; int low=nNum%10; *cA=low+'0'; if(high==0) return; else { Add(cA+1,high); } } void main() { char cA1[Max],cA2[Max],cA3[Max+Max]; int cA1length=0,cA2length=0; string str; for(int i=0; i<Max;++i) { cA1[i]='0'; cA2[i]='0'; } for(int i=0;i<Max*2;++i) { cA3[i]='0'; } cout<<"输入两个大数:"<<endl; cin>>str; for(int i=0;i<str.length();++i) { cA1length++; cA1[i]=str[str.length()-1-i]; } str.clear(); cin>>str; for(int i=0;i<str.length();++i) { cA2length++; cA2[i]=str[str.length()-1-i]; } for(int i=0;i<cA2length;++i) { for(int j=0;j<cA1length;++j) { int Temp=(cA2[i]-'0')*(cA1[j]-'0'); Add(cA3+i+j,Temp); } } int nUp=cA1length+cA2length; while(cA3[nUp]=='0') nUp--; while(nUp!=-1) { cout<<cA3[nUp]; nUp--; } }