2013.6.17大数计算之浮点数

#include <stdio.h>#include <string.h>void Swap(char &a,char &b){char c =a;a =b;b = c;}void ReverseString(char *s){int i=0;int j = strlen(s)-1;while (i<j){Swap(s[i],s[j]);i++;j--;}}void AddString(char *A,char *B,char *C){char AA[100];char BB[100];char CC[100];strcpy(AA,A);strcpy(BB,B);ReverseString(AA);ReverseString(BB);int posAA=-1;int posBB=-1;char *p = strchr(AA,'.');if (p!=NULL){posAA = p-AA;}char *q = strchr(BB,'.');if (q!=NULL){posBB = q-BB;}int lenCC=0;int len_float_min = posAA<posBB ? posAA : posBB;if (p==NULL || q==NULL){len_float_min=0;}int i=0,j=0;int carry = 0;while (posAA-i>len_float_min){int tmp = carry+AA[i]-'0';carry = tmp/10;CC[lenCC++] = tmp%10+'0';i++;}while (posBB-j>len_float_min){int tmp = carry+BB[j]-'0';carry = tmp/10;CC[lenCC++] = tmp%10+'0';j++;}while (i<posAA && j<posBB){int tmp = carry + AA[i]-'0'+BB[j]-'0';carry = tmp/10;CC[lenCC++] = tmp%10+'0';i++; j++;}CC[lenCC++] = '.';i++;j++;if (p==NULL){i=0;}if (q==NULL){j=0;}while (i<strlen(AA) && j<strlen(BB)){int tmp = carry + AA[i]-'0'+BB[j]-'0';carry = tmp/10;CC[lenCC++] = tmp%10+'0';i++; j++;}while (i<strlen(AA)){int tmp = carry+AA[i]-'0';carry = tmp/10;CC[lenCC++] = tmp%10+'0';i++;}while (j<strlen(BB)){int tmp = carry+BB[j]-'0';carry = tmp/10;CC[lenCC++] = tmp%10+'0';j++;}if (carry){CC[lenCC++]=carry+'0';}CC[lenCC]=0;ReverseString(CC);int cnt=0;for (i=0;i<strlen(CC);++i){if (CC[i]!='0') break;cnt++;}for (i=cnt;i<strlen(CC)+1;++i){CC[i-cnt] = CC[i];}cnt=0;for (i=strlen(CC)-1;i>=0;--i){if (CC[i]!='0') break;cnt++;}CC[strlen(CC)-cnt]=0;char *r = strchr(CC,'.');int pos = r-CC;if (pos==strlen(CC)-1){CC[strlen(CC)-1]=0;}strcpy(C,CC);}int main(){char s[300];char s1[100];char s2[100];char s3[100];//strcpy(s1,"1111.222");//strcpy(s2,"2222.333477777");scanf("%s",s);//strcpy(s,"1.2+3");int pos=0;char *p = strchr(s,'+');pos = p-s;int i=0;for (i=0;i<pos;++i){s1[i]=s[i];}s1[pos]=0;for (i=pos+1;i<strlen(s);++i){s2[i-pos-1] = s[i];}s2[strlen(s)-pos-1]=0;AddString(s1,s2,s3);printf("%s\n",s3);return 0;}