What does "undeclared identifier" mean?

[thistleryver]

I thought it meant that I hadn't declared a variable but I have.

int DoubleNumbers(int seq[], int *digitNum)
{
    int i, j;
 
    for (i = 0; i = 9; i++)
        for (j = i + 1; j = 9; j++)
            if (seq[i] == seq[j]){
                *digitNum = j;
                return 1;
            }
    return 0;
}
 

An error message comes up and says that both i and j are "undeclared identifiers". Can anyone help me?

[Banfa]

That code compiles fine for me, no problems, it must be a different bit of your code causeing the error.

[D_C]

for (i = 0; i = 9; i++)

should probably changed to

for (i = 0; i != 9; i++)

or

for (i = 0; i < 10; i++)

Similarly for j.

[shaikh riyaz]

u'r code , i thing it should be like that
for(i=0;i<10;i++)

[Banfa]

I thought it meant that I hadn't declared a variable but I have.

It does which is why I don't think this problem is in this section of code.

However take note of what everyone else has said or your code will enter an infinite loop.

[euxon]

Remember scope for "for"-loops.

int DoubleNumbers(int seq[], int *digitNum) 
{ 
    int i, j; 
 
    for (i = 0; i = 9; i++){ 
        for (j = i + 1; j = 9; j++){ 
            if (seq[i] == seq[j]){ 
                *digitNum = j; 
                return 1; 
            }
         }
    } 
    return 0; 
} 
 

[Banfa]

While adding braces in this manor is good practice in this particular instance adding those braces does not actually change the codes functionality.