大数相加

#define MaxLen 200char *BigNumPlus(char *a,char *b){int i,t; char fa[MaxLen],fb[MaxLen],ret[MaxLen];int lena=strlen(a),lenb=strlen(b);memset(ret,0,sizeof(ret));if (lenb>lena){strcpy(&fa[MaxLen-1-lenb],b);strcpy(&fb[MaxLen-1-lena],a);}else{strcpy(&fa[MaxLen-1-lena],a);strcpy(&fb[MaxLen-1-lenb],b);}if (lenb>lena){t=lena;lena=lenb;lenb=t;} for (i=MaxLen-2;i>=MaxLen-1-lena;i--){if (i>=MaxLen-1-lenb)ret[i]=fa[i]-0x30+fb[i]-0x30; elseret[i]=fa[i]-0x30;}for (i=MaxLen-2;i>=MaxLen-1-lena;i--) {if (ret[i]>=10){if (i==MaxLen-1-lena)lena++;ret[i]=ret[i]-10;ret[i-1]++;}ret[i]+=0x30;}while (ret[MaxLen-1-lena]=='0') lena--; return &ret[MaxLen-1-lena];}