【HDOJ】1753 大明A+B

注意数据格式，可以是整数，并且注意输出最简化浮点数。

 #include <stdio.h>
 #include <string.h>

 #define MAXNUM 420

 char a[MAXNUM], b[MAXNUM], c[MAXNUM], d[MAXNUM];
 int lena, lenb;
 int posa, posb;

 int addf(int bega, int begb, int *carry);
 int addi(int enda, int endb, int carry);
 void add();
 void output(int in, int fn);

 int main() {

     while (scanf("%s %s", a, b) != EOF) {
         add();
         memset(a, , sizeof(a));
         memset(b, , sizeof(b));
         memset(c, , sizeof(c));
         memset(d, , sizeof(d));
     }

     return ;
 }

 void add() {
     int i, carry, in, fn;

     posa = posb = -;
     for (i=; i<MAXNUM; ++i) {
         if (a[i] == '\0')
             break;
         else if (a[i] == '.')
             posa = i;
         else
             a[i] -= '';
     }
     lena = i;
     if (posa == -)
         posa = lena;

     for (i=; i<MAXNUM; ++i) {
         if (b[i] == '\0')
             break;
         else if (b[i] == '.')
             posb = i;
         else
             b[i] -= '';
     }
     lenb = i;
     if (posb == -)
         posb = lenb;

     fn = addf(posa+, posb+, &carry);
     in = addi(posa, posb, carry);
     output(in, fn);
 }

 void output(int in, int fn) {
     int i;

     // printf the integer part
     while (in>= && c[in]==)
             --in;
     if (in < )
         printf("");
     else {
         for (i=in; i>=; --i)
             printf("%d", c[i]);
     }

     fflush(stdout);
     // printf the float part
     while (fn>= && d[fn]==)
         --fn;
     if (fn>=) {
         printf(".");
         for (i=; i<=fn; ++i)
             printf("%d", d[i]);
     }
     printf("\n");
     fflush(stdout);
 }

 int addi(int enda, int endb, int carry) {
     int cn = ;

     while (enda || endb) {
         c[cn] += carry;
         if (enda) {
             --enda;
             c[cn] += a[enda];
         }
         if (endb) {
             --endb;
             c[cn] += b[endb];
         }
         carry = c[cn]/;
         c[cn] %= ;
         ++cn;
     }
     c[cn] += carry;

     return cn;
 }

 int addf(int bega, int begb, int *carry) {
     int i, len, ov = ;
     int flena = lena - bega;
     int flenb = lenb - begb;

     len = (flena>flenb) ? flena : flenb;

     for (i=len-; i>=; --i) {
         d[i] += ov;
         if (bega+i < lena)
             d[i] += a[bega+i];
         if (begb+i < lenb)
             d[i] += b[begb+i];
         ov = d[i]/;
         d[i] %= ;
     }

     *carry = ov;

     return len;
 }