大数加法

#define   _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include<stdlib.h>
#include<string.h>
//C语言声明变量需要加上stuct
//C语言结构内部不可以有函数
//C语言结构体没有公有，私有，继承






/// 加法，减法
/// 1234.567 ×12345.987
/// 15K+  除法，


//————————


void getbigdata(char *dataa, char* datab)
{
int lengtha = strlen(dataa);
int lengthb = strlen(datab);


if (lengtha < lengthb)
{
char* temp = NULL;
temp = dataa;
dataa = datab;
datab = temp;


int tem = lengtha;
lengtha = lengthb;
lengthb = tem;


}






int *pres = (int *)malloc(sizeof(int)*(lengtha + lengthb));






memset(pres, 0, sizeof(int)*(lengtha + lengthb));//初始化
//累乘














for (int i = lengtha ,j=lengthb,k=1; i >= 0||j>=0; i--,j--,k++)
{
//for (int j = 0; j < lengthb; j++)
{
pres[lengtha + lengthb-k] = (dataa[i] - '0') + (datab[j] - '0');
}
if (j==0)
{
for (--i; i >= 0; i--,k++)
{
pres[lengtha + lengthb - k-1] = (dataa[i] - '0');
}
}






}








//进位
for (int i = lengtha + lengthb - 1; i >= 0; i--)
{
if (pres[i] >= 10)//进位
{
pres[i - 1] += pres[i] / 10;//进位
pres[i] %= 10;//取出个位数
}


}




















int i = 0;
while (pres[i] == 0)
{
i++;//恰好不为0的位置
}








char *lastres = malloc(sizeof(char)*(lengtha + lengthb));
int j;






for (j = 0; j < lengtha+1; j++, i++)
{
lastres[j] = pres[i] + '0';
}
     lastres[j] = '\0';
printf("last结果=%s", lastres);








}










void main()
{
char str1[100] = { 0 };
char str2[100] = { 0 };
scanf("%s%s", str1, str2);
printf("str1=%s,str2=%s", str1, str2);//打印结果
getbigdata(str1, str2);


//strcpy(str1, "123123");


system("pause");




}