initialize all elements of char_freq [ ] to 0
for ( let i = 0 ; i < SIZE ; i ++ ) char_freq [ i ] = 0 ; let nv = 0 , nc = 0 ; let vstr = " " , cstr = " " ; let l = str . length ; for ( let i = 0 ; i < l ; i ++ ) { let ch = str [ i ] ;