Checking for palindrome between two indices

Question

I am trying to check whether a the string contains palindrome between the given indices. However I am unable to find the bug in my code.

bool isPal(char a[],int i,int j){

    for(int k=i;k<(j-i)/2;k++)
        if(a[k]!=a[j--])
            return 0;

    return 1;
}

Answer 1

You error was to increment j as but also assume (in the loop condition) that it remains at its input value. You could use the input variables also as loop variables

bool isPalindrome(const char*a, int i, int j) {
    while(i<j)
        if(a[i++] != a[j--])
            return false;
    return true;
}

when setting the correct stop conditions for the loop is straightforward.