【C语言代码】大数求和

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

/************ 前后倒置函数 ***************/
void reverse(char *str)
{
unsigned int i,j;
char c;
for(i = 0 , j = strlen(str)-1; i < j; i++,j--)
{
c = str[i]; str[i] = str[j]; str[j] = c ;
}
}

void main()
{
char str1[100], str2[100],str[101];
char *p1 = NULL, *p2 = NULL,*p = NULL;
unsigned int len1 = 0,len2 = 0,len = 0;
unsigned int i = 0;

printf("input the first number : ");
scanf("%s",str1);
printf("input the second number : ");
scanf("%s",str2);

len1 = strlen(str1);
len2 = strlen(str2);

if(len1 > 100 || len2 > 100)
return;

len = len1 > len2 ? len1 : len2 ;
/********** 补0 ************/
reverse(str1);
reverse(str2);

for(i = len1 ; i < len + 1; i++)
{
str1[i] = '0';
}
str1[i] = '\0';
for(i = len2 ; i < len + 1; i++)
{
str2[i] = '0';
}
str2[i] = '\0';

/***** 从最低位开始相加，一直加到最前端的0 ******/
p1 = str1 ;
p2 = str2 ;
p  = str ;

while(*p1 != '\0')
{
*p = (*p1 -48) + (*p2 - 48) ;
if(*p >= 10)
{
*p = *p - 10;
p2 ++;
*p2 = *p2 + 1;
}
else
p2 ++ ;
*p = *p + 48 ;

p1 ++;
p ++;
}
*p = '\0';

len = strlen(str);
reverse(str);
if(str[0] == '0')
for(i = 0; i < len; i++)
str[i] = str[i+1];
puts(str);

}