E.F.G.H.Checking that identifiers are declared before their useNumber of formal parameters in the declaration of a function agrees with the number of actual parametersin a use of that functionArithmetic expressions with matched pairs of parenthesesPalindromesP.Q.R.S.L={anbmcndm∣n≥1,m≥1}X→XbX∣XcX∣dXf∣gL={wcw∣w∈(a∣b)∗}X→bXb∣cXc∣ϵ