C backend: Implement string type for declarations

Author: certik

src/libasr/codegen/asr_to_c.cpp

@@ -114,7 +114,9 @@ class ASRToCVisitor : public BaseCCPPVisitor<ASRToCVisitor>
                 std::string dims = convert_dims_c(t->n_dims, t->m_dims);
                 sub = format_type_c(dims, "bool", v.m_name, use_ref, dummy);
             } else if (ASRUtils::is_character(*v.m_type)) {
-                // TODO
+                ASR::Character_t *t = ASR::down_cast<ASR::Character_t>(v.m_type);
+                std::string dims = convert_dims_c(t->n_dims, t->m_dims);
+                sub = format_type_c(dims, "char *", v.m_name, use_ref, dummy);
             } else if (ASR::is_a<ASR::Derived_t>(*v.m_type)) {
                 std::string indent(indentation_level*indentation_spaces, ' ');
                 ASR::Derived_t *t = ASR::down_cast<ASR::Derived_t>(v.m_type);