/*大数加法*/ # include<stdio.h># include<string.h># include<malloc.h>void add(char* a,char* b,char* c){    int i,j,k,max,min,n,temp;    char *s,*pmax,*pmin;    max=strlen(a);    min=strlen(b);    if (max<min)    {        temp=max;        max=min;        min=temp;        pmax=b;        pmin=a;    }    else    {        pmax=a;        pmin=b;    }    s=(char*)malloc(sizeof(char)*(max+1));    s[0]=‘0‘;    for (i=min-1,j=max-1,k=max;i>=0;i--,j--,k--)        s[k]=pmin[i]-‘0‘+pmax[j];       for (;j>=0;j--,k--)           s[k]=pmax[j];    for (i=max;i>=0;i--)        if (s[i]>‘9‘)        {            s[i]-=10;            s[i-1]++;        }    if (s[0]==‘0‘)    {        for (i=0;i<=max;i++)            c[i-1]=s[i];           c[i-1]=‘\0‘;    }    else    {        for (i=0;i<=max;i++)            c[i]=s[i];           c[i]=‘\0‘;    }    free(s);}/*大数减法*/ void subtract(char* a,char* b,char* c){    int i,j,ca,cb;    ca=strlen(a);    cb=strlen(b);    if (ca>cb||(ca==cb&&strcmp(a,b)>=0))    {        for (i=ca-1,j=cb-1;j>=0;i--,j--)            a[i]-=(b[j]-‘0‘);           for (i=ca-1;i>=0;i--)               if (a[i]<‘0‘)               {                   a[i]+=10;                   a[i-1]--;            }        i=0;        while (a[i]==‘0‘)            i++;           if (a[i]==‘\0‘)          {              c[0]=‘0‘;              c[1]=‘\0‘;        }        else        {            for (j=0;a[i]!=‘\0‘;i++,j++)                c[j]=a[i];               c[j]=‘\0‘;        }    }    else    {        for (i=ca-1,j=cb-1;i>=0;i--,j--)            b[j]-=(a[i]-‘0‘);           for (j=cb-1;j>=0;j--)               if (b[j]<‘0‘)               {                   b[j]+=10;                   b[j-1]--;            }        j=0;        while (b[j]==‘0‘)            j++;           i=1;           c[0]=‘-‘;           for (;b[j]!=‘\0‘;i++,j++)               c[i]=b[j];          c[i]=‘\0‘;    }            }/* 大数乘法*/ void multiply(char* a,char* b,char* c){    int i,j,ca,cb,* s;    ca=strlen(a);    cb=strlen(b);    s=(int*)malloc(sizeof(int)*(ca+cb));    for (i=0;i<ca+cb;i++)        s[i]=0;    for (i=0;i<ca;i++)        for (j=0;j<cb;j++)            s[i+j+1]+=(a[i]-‘0‘)*(b[j]-‘0‘);    for (i=ca+cb-1;i>=0;i--)        if (s[i]>=10)        {            s[i-1]+=s[i]/10;            s[i]%=10;        }    i=0;    while (s[i]==0)        i++;       for (j=0;i<ca+cb;i++,j++)           c[j]=s[i]+‘0‘;    c[j]=‘\0‘;    free(s);}/*大数除法,返回余数*/int dividor(char* a,int b,char* c){    int i,j,temp=0,n;    char* s;    n=strlen(a);    s=(char*)malloc(sizeof(char)*(n+1));    for (i=0;a[i]!=0;i++)       {           temp=temp*10+a[i]-‘0‘;           s[i]=temp/b+‘0‘;           temp%=b;    }    s[i]=‘\0‘;    for (i=0;s[i]==‘0‘&&s[i]!=‘\0‘;i++);    if (s[i]==‘\0‘)    {        c[0]=‘0‘;        c[1]=‘\0‘;    }    else    {        for (j=0;s[i]!=‘\0‘;i++,j++)            c[j]=s[i];           c[j]=‘\0‘;    }    free(s);    return temp;}