Can anyone of you give me source code for a sudoku in C++ ? I need it for my practicals at school. I just need to look at the code to understand the logic behind the program.

Please find me one as soon as possible.

* SU DOKU */

#include <iostream.h>
void main()
{
int k[9][9],K[9][9];
int i,j,i1,j1,i2,j2;
int error,temp;
int count=0;

for(i=0;i<9;i++)
for(j=0;j<9;j++)
K[i][j]=0;

for(i=0;i<9;i++)
for(j=0;j<9;j++)
{
cin>>K[i][j];
k[i][j]=K[i][j];
}
cout<<"O.K.? (Enter 0 if OK, 1 to update): ";
cin>>error;
if(error==0)
goto matrixvalidation;

matrixupdation:
while(1)
{
cout<<"Enter Row, Col, Revised number0 to exit) ";
cin>>i;
if(i==0)break;
cin>>j>>temp;
if(i>0&&j>0&&temp>=0&&i<10&&j<10&&temp<10)
{
K[i-1][j-1]=temp;
k[i-1][j-1]=temp;
}
else
cout<<"Enter row/column 1 to 9 & number 0 to 9 only.
";
}

matrixvalidation:
cout<<"
Input matrix:
";
for(i=0;i<9;i++)
{
for(j=0;j<9;j++)
cout<<k[i][j]<<" ";
cout<<"
";
}

for(i=0;i<9;i++)
for(j=0;j<9;j++)
if(k[i][j]<0||k[i][j]>9)
{
cout<<"
"<<i+1<<" "<<j+1<<" "<<k[i][j];
cout<<"
Input matrix error.";
cout<<"
Numbers should be 1 to 9 only.

";
goto matrixupdation;
}

for(i=0;i<9;i++)
for(j=0;j<9;j++)
{
if(k[i][j]==0)continue;
error=0;
for(i1=0;i1<9;i1++)
if(i!=i1&&k[i][j]==k[i1][j])
{
error=1;
i2=i1;
j2=j;
}
for(j1=0;j1<9;j1++)
if(j!=j1&&k[i][j]==k[i][j1])
{
error=1;
i2=i;
j2=j1;
}
for(i1=0;i1<9;i1++)
for(j1=0;j1<9;j1++)
if((i!=i1||j!=j1)&&i/3==i1/3&&j/3==j1/3&&k[i][j]==k[i1][j1])
{
error=1;
i2=i1;
j2=j1;
}
if(error)
{
cout<<"
"<<i+1<<" "<<j+1<<" "<<k[i][j];
cout<<"
"<<i2+1<<" "<<j2+1<<" "<<k[i2][j2];
cout<<"
Input matrix error.";
cout<<"
A number has been repeated in the same row, col or
block.

";
goto matrixupdation;
}
}

/* Logic starts: */
for(i=0;i<9;i++)
for(j=0;j<9;j++)
{
if(K[i][j]>0) goto chksol;
for(k[i][j]++;k[i][j]<=9;k[i][j]++)
{
error=0;
for(i1=0;i1<9;i1++)
if(i!=i1&&k[i][j]==k[i1][j])error=1;
for(j1=0;j1<9;j1++)
if(j!=j1&&k[i][j]==k[i][j1])error=1;
for(i1=0;i1<9;i1++)
for(j1=0;j1<9;j1++)
if((i!=i1||j!=j1)&&i/3==i1/3&&j/3==j1/3&&k[i][j]==k[i1][j1])
error=1;
if(error==0)break;
}
if(k[i][j]>9)
{
k[i][j]=0;
do
{
if(i==0&&j==0)goto nomoresol;
if(j>0)j--;else{j=8;i--;}
}while(K[i][j]>0);
j--;
}
chksol: if(i==8&&j==8)
{
cout<<"
Solution: "<<++count<<"
";
for(i1=0;i1<9;i1++)
{
for(j1=0;j1<9;j1++)
cout<<k[i1][j1]<<" ";
cout<<"
";
}
if(count==50)
{
cout<<"
Too many solutions.
Not checking for more
solutions.

";
return;
}

while(K[i][j]>0)
{
if(i==0&&j==0)goto nomoresol;
if(j>0)j--;else{j=8;i--;}
}
k[i][j]=0;
do
{
if(i==0&&j==0)goto nomoresol;
if(j>0)j--;else{j=8;i--;}
}while(K[i][j]>0);
j--;
}
}
nomoresol:
if(count>0)
cout<<"
No more solutions.

";
else
cout<<"No solution.

";
}