Pointer -- output all characters in the string in reverse order

requirement

Programming , Enter a string , Output all characters in reverse order .（ Use a pointer to achieve ）

Code

/* *  This function implements string a Reverse operation of , If the original string is string, Reverse order followed by gnirts, *  Please store the string after reverse order in a In what it points to  */
void reverse(char *a)
{
    
    int n = strlen(a);
    int b[n],c = 0;
    for(int i = n-1;i>=0;i--)
    {
    
        b[c] = a[i];
        c++;
    }
    for(int i = 0;i<n;i++)
    {
    
        a[i] = b[i];
    }   
}

main function

int main()
 {
    
     char a[200];
     gets(a);
     reverse(a);
     puts(a);
    return 0;
 }   

test

Test input
I am a student
Output
tneduts a ma I