大一下期末考试 : 大数存储 超长整数的加法

#include<stdio.h>
#include<string.h>
#define N 100
main()
{
char a
={'0'},b
={'0'},sum
={'0'};
int an,bn,flag=0,max;
printf("Please input one strings:");
scanf("%s",a);
printf("Please input another strings:");
scanf("%s",b);
an=strlen(a)-1;
bn=strlen(b)-1;
max=an>bn?an:bn;
while(max>=0)
{
if(an>=0&&bn>=0)
{
if(a[an]-'0'+b[bn]-'0'+flag>9)
{
sum[max]=a[an]-'0'+b[bn]-10+flag;
flag=1;
}
else
{
sum[max]=a[an]+b[bn]-'0'+flag;
flag=0;
}
an--;
bn--;
}
else
{
if(an>=0&&bn<0)
{
if(a[an]-'0'+flag>9)
{
sum[max]='0';
flag=1;
}
else
{
sum[max]=a[an]+flag;
flag=0;
}
an--;
}
else if(bn>=0&&an<0)
{
if(b[bn]-'0'+flag>9)
{
sum[max]='0';
flag=1;
}
else
{
sum[max]=b[bn]+flag;
flag=0;
}
bn--;
}
}
max--;
}
if(flag)
printf("the sum : 1%s",sum);
else
printf("the sum : %s",sum);

}

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