uva 748 - Exponentiation 带小数点的大数乘法

来源：互联网发布：mac队编辑：程序博客网时间：2024/05/09 22:50

实数的大数乘法就多一个定位小数点输出的时候不输出前导和后导零所以大数乘法模版很重要

下面直接上代码

#include<cstdio>#include<cmath>#include<cstring>#include<algorithm>using namespace std;int point;//小数点的最终位置int  zero(char *l)//控制后导零不输出{    int i;    for(i = 0; l[i]=='0' ;i++);    return i;}void print(char *p, int p_len){    char str[200],str_len = 0;    for(int i = 0;i < p_len; i++)    {        if(i == point)str[str_len++] = '.';//补上小数点        str[str_len++] = p[i];    }    int i = str_len-1;    for(i = str_len-1; str[i] == '0'; i--);//加上这条输出时去掉前导零    for( ;i >= zero(str); i--)        printf("%c",str[i]);    printf("\n");}int  re_order(char *p, int p_len, char *q)//逆序存储p到q中{    int q_len = 0;    for(int i = p_len-1; i >= 0; i--)    {        if(p[i] == '.')continue;//去掉小数点        q[q_len++]=p[i];    }    q[q_len]='\0';    return q_len;}void  multi(char *p, int  p_len, int N){    char str[200];    int  num[200],i, j, t;    int str_len = p_len,sum;    strcpy(str,p);    for(t = 0; t < N-1; t++)//N个数相乘    {        sum = 0;        memset(num,0,sizeof(num));//这一定要初始化为零  要不容易Wrong的        for(i = 0; i < p_len; i++)            for(j = 0; j < str_len; j++)                num[i+j] += (p[i]-'0')*(str[j]-'0');        for(i = 0; i < p_len+str_len; i++)        {            sum += num[i];            str[i] = sum%10+'0';            sum /= 10;        }        str_len = i;        str[i]='\0';    }    print(str,str_len);}int main(){    #ifdef LOCAL    freopen("in1.txt","r",stdin);    #endif // LOCAL    char str[10],s[10];    int N;    while(scanf("%s%d\n",str,&N)!=EOF)    {        int str_len = strlen(str);        for(int i = 0; i < str_len; i++)            if(str[i] == '.'){point  = (str_len -i -1)*N;break;}        int s_len = re_order(str, str_len, s);        multi(s,s_len,N);    }    return 0;}