how to look for the index of a vector in an array

[ajaythk]

int D[5][3] ={

{1, 0, 0},

{0, 1, 0},

{0, 0, 1},

{0, 0, 0},

{0, 0, 0},

};

int classnum=0;

int Sy[1][3]={0 ,0 ,1};


for(int i=0 ;i <5 ;i++)
{
for(int j=0 ;j < 3 ;j++)

{
if(Sy[0][j]== D[i][j])

{
classnum = i;

}
}
}
cout<<"\nclassnum = "<<classnum;

it always shows the classnum=4,it should rather be 2.what is the error i am making?

[ne555]

you would benefit by drawing the flow diagram and doing an step-by-step execution

Suppose that i=4, then we have

	for (int j = 0; j < 3; j++)
	{
		if (Sy[0][j] == D[4][j])
		{
			classnum = 4;
		}
	}

when j=0, the condition is if (Sy[0][0] == D[4][0]), replacing if( 0 == 0 ) which is true, and classnum is set to 4.


You are checking if any element matches, when you should check that they all match.

[ajaythk]

if you could help me with this...?

[MikeyBoy]

Um... he did.

[Chervil]

You could use a bool variable as a flag. Set it to true at the start of each pass of the outer loop .

If any element is not equal, set the flag to false. If it is still set to true after checking all three elements, you have a match.