Dear all,

I have been having trouble with this code . This program is supposed to brute-force verbal arithmetic, but when it is testing large numbers, the values in array x1 screw up badly. They become negative and I have given up. Could anyone please tell me what's wrong? This same error came up in another program I tried to write.

Code:

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int pows(int a,int b)
{
int p=1;
for(;b>0;b--)
{
p*=a;
}
return p;
}
int check(int data[],int dataCheck[],int k)
{
int i;
int flag=1;
for(i=0;i<k;i++)
{
if(data[i]!=dataCheck[i])
{
flag=0;
break;
}
}
return flag;
}
int sortNum(int x1[],int x)
{
int i,j;
int y=x;
for(i=0;x!=0;i++)
{
x/=10;
}
x1[i]=10;
x1[i+1]=10;
j=i;
for(i--;i>=0;i--)
{
x1[i]=y%10;
y/=10;
}
return j;
}
int main()
{
char a[30],b[30],c[30];
char x[30];
int x1[30];
int aNum,bNum,cNum;
int data[60]={0},dataCheck[59]={0};
int aLen,bLen,cLen;
int cLent,cNumt;
int xLen;
int i,j,m,k=0,k1=0;
fgets(a,10,stdin);
fgets(b,10,stdin);
fgets(c,11,stdin);
aLen=strlen(a);
bLen=strlen(b);
cLen=strlen(c);
a[aLen-1]='\0';
b[bLen-1]='\0';
strcpy(x,a);
strcat(x,b);
strcat(x,c);
for(i=0;x[i]!='\n';i++)
{
for(j=i+1;x[j]!='\n';j++)
{
if(x[i]==x[j])
{
data[k]=i;
data[k+1]=j;
k+=2;
break;
}
}
}
for(m=0;m<pows(10,aLen+bLen-2);m++)
{
aNum=m%(pows(10,aLen-1));
bNum=(m-aNum)/pows(10,aLen-1);
cNum=aNum+bNum;
cNumt=cNum;
for(cLent=0;cNumt!=0;cLent++)
{
cNumt/=10;
}
xLen=sortNum(x1,(aNum*pows(10,bLen+cLent-1)+bNum*pows(10,cLent)+cNum));
if(xLen!=aLen+bLen+cLen-3)
{
continue;
}
for(i=0,k1=0;i<xLen;i++)
{
for(j=i+1;j<xLen;j++)
{
if(x1[j]==x1[i])
{
dataCheck[k1]=i;
dataCheck[k1+1]=j;
k1+=2;
break;
}
}
}
if(k!=k1)
{
continue;
}
if(check(data,dataCheck,k)==1)
{
printf("%d+%d=%d\n",aNum,bNum,cNum);
}
}
return 0;
}