diff --git a/.clang-format b/.clang-format
index 9a036c2..0995233 100644
--- a/.clang-format
+++ b/.clang-format
@@ -8,3 +8,11 @@ UseTab: Never
 PointerAlignment: Left
 IndentCaseLabels: true
 AlwaysBreakTemplateDeclarations: Yes
+InsertBraces: true
+SortIncludes: true
+# system headers come first
+IncludeCategories:
+  - Regex: "^<.*>"
+    Priority: 1
+  - Regex: '^".*\.(h|hpp)"'
+    Priority: 2
diff --git a/prettyprint.sh b/prettyprint.sh
index b0976d7..a14ac3a 100755
--- a/prettyprint.sh
+++ b/prettyprint.sh
@@ -1,7 +1,9 @@
 #!/usr/bin/env bash
 
+# $@ - List of directories
+
 # Code beautifier with clang-format
-# Recursively parses the folder(s) passed as command line argument(s)
+# Recursively parses the directories passed as command line arguments
 
 if test -z "$CLANG_FORMAT"; then
     echo "Please set the CLANG_FORMAT environment variable to point to the \
diff --git a/qasmtools/include/qasmtools/ast/decl.hpp b/qasmtools/include/qasmtools/ast/decl.hpp
index ad83809..da4ee36 100644
--- a/qasmtools/include/qasmtools/ast/decl.hpp
+++ b/qasmtools/include/qasmtools/ast/decl.hpp
@@ -162,8 +162,9 @@ class GateDecl final : public Stmt, public Decl {
      * \param f A void function taking a reference to a Gate
      */
     void foreach_stmt(std::function<void(Gate&)> f) {
-        for (auto it = body_.begin(); it != body_.end(); it++)
+        for (auto it = body_.begin(); it != body_.end(); it++) {
             f(**it);
+        }
     }
 
     /**
@@ -183,8 +184,9 @@ class GateDecl final : public Stmt, public Decl {
     void accept(Visitor& visitor) override { visitor.visit(*this); }
     std::ostream& pretty_print(std::ostream& os,
                                bool suppress_std) const override {
-        if (suppress_std && is_std_qelib(id_))
+        if (suppress_std && is_std_qelib(id_)) {
             return os;
+        }
 
         os << (opaque_ ? "opaque " : "gate ") << id_;
         if (c_params_.size() > 0) {
@@ -381,8 +383,9 @@ class AncillaDecl final : public Gate, public Decl {
 
     void accept(Visitor& visitor) override { visitor.visit(*this); }
     std::ostream& pretty_print(std::ostream& os, bool) const override {
-        if (dirty_)
+        if (dirty_) {
             os << "dirty ";
+        }
         os << "ancilla " << id_ << "[" << size_ << "];\n";
         return os;
     }
diff --git a/qasmtools/include/qasmtools/ast/expr.hpp b/qasmtools/include/qasmtools/ast/expr.hpp
index fbf6ed0..6dd98a3 100644
--- a/qasmtools/include/qasmtools/ast/expr.hpp
+++ b/qasmtools/include/qasmtools/ast/expr.hpp
@@ -200,8 +200,9 @@ class BExpr final : public Expr {
         auto lexp = lexp_->constant_eval();
         auto rexp = rexp_->constant_eval();
 
-        if (!lexp || !rexp)
+        if (!lexp || !rexp) {
             return std::nullopt;
+        }
 
         switch (op_) {
             case BinaryOp::Plus:
@@ -293,8 +294,9 @@ class UExpr final : public Expr {
     std::optional<double> constant_eval() const override {
         auto expr = exp_->constant_eval();
 
-        if (!expr)
+        if (!expr) {
             return std::nullopt;
+        }
 
         switch (op_) {
             case UnaryOp::Neg:
@@ -320,9 +322,9 @@ class UExpr final : public Expr {
         (void)ctx;
 
         os << op_;
-        if (op_ == UnaryOp::Neg)
+        if (op_ == UnaryOp::Neg) {
             exp_->pretty_print(os, true);
-        else {
+        } else {
             os << "(";
             exp_->pretty_print(os, false);
             os << ")";
diff --git a/qasmtools/include/qasmtools/ast/program.hpp b/qasmtools/include/qasmtools/ast/program.hpp
index bca5b35..ddac85c 100644
--- a/qasmtools/include/qasmtools/ast/program.hpp
+++ b/qasmtools/include/qasmtools/ast/program.hpp
@@ -99,8 +99,9 @@ class Program : public ASTNode {
      * \param f Void function accepting a reference to a statement
      */
     void foreach_stmt(std::function<void(Stmt&)> f) {
-        for (auto it = body_.begin(); it != body_.end(); it++)
+        for (auto it = body_.begin(); it != body_.end(); it++) {
             f(**it);
+        }
     }
 
     /**
@@ -120,8 +121,9 @@ class Program : public ASTNode {
     void accept(Visitor& visitor) override { visitor.visit(*this); }
     std::ostream& pretty_print(std::ostream& os) const override {
         os << "OPENQASM 2.0;\n";
-        if (std_include_)
+        if (std_include_) {
             os << "include \"qelib1.inc\";\n";
+        }
         os << "\n";
         for (auto it = body_.begin(); it != body_.end(); it++) {
             (*it)->pretty_print(os, std_include_);
diff --git a/qasmtools/include/qasmtools/ast/replacer.hpp b/qasmtools/include/qasmtools/ast/replacer.hpp
index 40ee4b7..8838d31 100644
--- a/qasmtools/include/qasmtools/ast/replacer.hpp
+++ b/qasmtools/include/qasmtools/ast/replacer.hpp
@@ -359,10 +359,11 @@ class GateReplacer final : public Replacer {
     std::optional<std::list<ptr<Gate>>> replace_gate(Gate& gate) {
         auto it = replacements_.find(gate.uid());
 
-        if (it != replacements_.end())
+        if (it != replacements_.end()) {
             return std::move(it->second);
-        else
+        } else {
             return std::nullopt;
+        }
     }
 };
 
diff --git a/qasmtools/include/qasmtools/ast/semantic.hpp b/qasmtools/include/qasmtools/ast/semantic.hpp
index 2c68357..75d842f 100644
--- a/qasmtools/include/qasmtools/ast/semantic.hpp
+++ b/qasmtools/include/qasmtools/ast/semantic.hpp
@@ -333,8 +333,9 @@ class SemanticChecker final : public Visitor {
      * \param typ The type of the symbol
      */
     void set(const ast::symbol& id, Type typ) {
-        if (symbol_table_.empty())
+        if (symbol_table_.empty()) {
             throw std::logic_error("No current symbol table!");
+        }
 
         symbol_table_.front()[id] = typ;
     }
@@ -467,8 +468,9 @@ class SemanticChecker final : public Visitor {
  */
 inline void check_source(Program& prog) {
     SemanticChecker analysis;
-    if (analysis.run(prog))
+    if (analysis.run(prog)) {
         throw SemanticError();
+    }
 }
 
 } /* namespace ast */
diff --git a/qasmtools/include/qasmtools/ast/stmt.hpp b/qasmtools/include/qasmtools/ast/stmt.hpp
index 0b3b93c..e4ae2ef 100644
--- a/qasmtools/include/qasmtools/ast/stmt.hpp
+++ b/qasmtools/include/qasmtools/ast/stmt.hpp
@@ -499,8 +499,9 @@ class BarrierGate final : public Gate {
      * \param f Void function accepting a reference to the argument
      */
     void foreach_arg(std::function<void(VarAccess&)> f) {
-        for (auto it = args_.begin(); it != args_.end(); it++)
+        for (auto it = args_.begin(); it != args_.end(); it++) {
             f(*it);
+        }
     }
 
     /**
@@ -612,8 +613,9 @@ class DeclaredGate final : public Gate {
      * \param f Void function accepting an expression reference
      */
     void foreach_carg(std::function<void(Expr&)> f) {
-        for (auto it = c_args_.begin(); it != c_args_.end(); it++)
+        for (auto it = c_args_.begin(); it != c_args_.end(); it++) {
             f(**it);
+        }
     }
 
     /**
@@ -622,8 +624,9 @@ class DeclaredGate final : public Gate {
      * \param f Void function accepting a reference to an argument
      */
     void foreach_qarg(std::function<void(VarAccess&)> f) {
-        for (auto it = q_args_.begin(); it != q_args_.end(); it++)
+        for (auto it = q_args_.begin(); it != q_args_.end(); it++) {
             f(*it);
+        }
     }
 
     /**
diff --git a/qasmtools/include/qasmtools/ast/traversal.hpp b/qasmtools/include/qasmtools/ast/traversal.hpp
index 794a3ef..e552234 100644
--- a/qasmtools/include/qasmtools/ast/traversal.hpp
+++ b/qasmtools/include/qasmtools/ast/traversal.hpp
@@ -83,27 +83,32 @@ class Traverse : public Visitor {
         gate.tgt().accept(*this);
     }
     void visit(BarrierGate& gate) override {
-        for (int i = 0; i < gate.num_args(); i++)
+        for (int i = 0; i < gate.num_args(); i++) {
             gate.arg(i).accept(*this);
+        }
     }
     void visit(DeclaredGate& gate) override {
-        for (int i = 0; i < gate.num_cargs(); i++)
+        for (int i = 0; i < gate.num_cargs(); i++) {
             gate.carg(i).accept(*this);
-        for (int i = 0; i < gate.num_qargs(); i++)
+        }
+        for (int i = 0; i < gate.num_qargs(); i++) {
             gate.qarg(i).accept(*this);
+        }
     }
 
     void visit(GateDecl& decl) override {
-        for (auto it = decl.begin(); it != decl.end(); it++)
+        for (auto it = decl.begin(); it != decl.end(); it++) {
             (**it).accept(*this);
+        }
     }
 
     void visit(OracleDecl& decl) override {}
     void visit(RegisterDecl& decl) override {}
     void visit(AncillaDecl& decl) override {}
     void visit(Program& prog) override {
-        for (auto it = prog.begin(); it != prog.end(); it++)
+        for (auto it = prog.begin(); it != prog.end(); it++) {
             (**it).accept(*this);
+        }
     }
 };
 
diff --git a/qasmtools/include/qasmtools/ast/var.hpp b/qasmtools/include/qasmtools/ast/var.hpp
index 3f152bd..8301544 100644
--- a/qasmtools/include/qasmtools/ast/var.hpp
+++ b/qasmtools/include/qasmtools/ast/var.hpp
@@ -113,10 +113,11 @@ class VarAccess final : public ASTNode {
      * Used to allow variable accesses as keys in ordered maps
      */
     bool operator<(const VarAccess& v) const {
-        if (var_ == v.var_)
+        if (var_ == v.var_) {
             return offset_ < v.offset_;
-        else
+        } else {
             return var_ < v.var_;
+        }
     }
 
     /**
@@ -130,10 +131,11 @@ class VarAccess final : public ASTNode {
      * \return true if the variable access contains v
      */
     bool contains(const VarAccess& v) const {
-        if (offset_)
+        if (offset_) {
             return *this == v;
-        else
+        } else {
             return v.var_ == var_;
+        }
     }
 
     /**
@@ -157,8 +159,9 @@ class VarAccess final : public ASTNode {
     void accept(Visitor& visitor) override { visitor.visit(*this); }
     std::ostream& pretty_print(std::ostream& os) const override {
         os << var_;
-        if (offset_)
+        if (offset_) {
             os << "[" << *offset_ << "]";
+        }
         return os;
     }
 
diff --git a/qasmtools/include/qasmtools/parser/lexer.hpp b/qasmtools/include/qasmtools/parser/lexer.hpp
index 3715847..5343d7c 100644
--- a/qasmtools/include/qasmtools/parser/lexer.hpp
+++ b/qasmtools/include/qasmtools/parser/lexer.hpp
@@ -95,10 +95,11 @@ class Lexer {
         }
 
         pos_.advance_column(consumed);
-        if (consumed != 0)
+        if (consumed != 0) {
             return true;
-        else
+        } else {
             return false;
+        }
     }
 
     /**
diff --git a/qasmtools/include/qasmtools/parser/parser.hpp b/qasmtools/include/qasmtools/parser/parser.hpp
index 11cbd6c..4b21cc4 100644
--- a/qasmtools/include/qasmtools/parser/parser.hpp
+++ b/qasmtools/include/qasmtools/parser/parser.hpp
@@ -84,12 +84,14 @@ class Parser {
     ast::ptr<ast::Program> parse(bool check = true) {
         // Parse the program
         auto result = parse_program();
-        if (error_)
+        if (error_) {
             throw ParseError();
+        }
 
         // Perform semantic analysis before returning
-        if (check)
+        if (check) {
             ast::check_source(*result);
+        }
 
         return result;
     }
@@ -102,8 +104,9 @@ class Parser {
      */
     void consume_token(bool reset = false) {
         current_token_ = pp_lexer_.next_token();
-        if (reset)
+        if (reset) {
             supress_errors_ = false;
+        }
     }
 
     /**
diff --git a/qasmtools/include/qasmtools/parser/preprocessor.hpp b/qasmtools/include/qasmtools/parser/preprocessor.hpp
index 8d77d05..2b806da 100644
--- a/qasmtools/include/qasmtools/parser/preprocessor.hpp
+++ b/qasmtools/include/qasmtools/parser/preprocessor.hpp
@@ -248,8 +248,9 @@ class Preprocessor {
         }
 
         auto target = token.as_string();
-        if (target == "qelib1.inc")
+        if (target == "qelib1.inc") {
             std_include_ = true;
+        }
 
         token = current_lexer_->next_token();
         if (token.is_not(Token::Kind::semicolon)) {
diff --git a/qasmtools/include/qasmtools/tools/ast_printer.hpp b/qasmtools/include/qasmtools/tools/ast_printer.hpp
index 53e562e..50c2dfa 100644
--- a/qasmtools/include/qasmtools/tools/ast_printer.hpp
+++ b/qasmtools/include/qasmtools/tools/ast_printer.hpp
@@ -47,8 +47,9 @@ class ASTPrinter final : public ast::Visitor {
     // Variables
     void visit(ast::VarAccess& ap) {
         os_ << prefix_ << "|- Var(" << ap.var();
-        if (ap.offset())
+        if (ap.offset()) {
             os_ << "[" << *ap.offset() << "]";
+        }
         os_ << ")\n";
     }
 
@@ -153,14 +154,17 @@ class ASTPrinter final : public ast::Visitor {
     // Declarations
     void visit(ast::GateDecl& decl) {
         os_ << prefix_ << "|- Gate Decl(" << decl.id() << "(";
-        for (auto& param : decl.c_params())
+        for (auto& param : decl.c_params()) {
             os_ << param << ",";
+        }
         os_ << ")[";
-        for (auto& param : decl.q_params())
+        for (auto& param : decl.q_params()) {
             os_ << param << ",";
+        }
         os_ << "]";
-        if (decl.is_opaque())
+        if (decl.is_opaque()) {
             os_ << ", opaque";
+        }
         os_ << ")\n";
 
         prefix_ += "  ";
@@ -170,24 +174,27 @@ class ASTPrinter final : public ast::Visitor {
 
     void visit(ast::OracleDecl& decl) {
         os_ << prefix_ << "|- Oracle Decl(" << decl.id() << "[";
-        for (auto& param : decl.params())
+        for (auto& param : decl.params()) {
             os_ << param << ",";
+        }
         os_ << "] = " << decl.fname() << ")\n";
     }
 
     void visit(ast::RegisterDecl& decl) {
         os_ << prefix_ << "|- Register Decl(" << decl.id() << "[" << decl.size()
             << "]";
-        if (decl.is_quantum())
+        if (decl.is_quantum()) {
             os_ << ", quantum";
+        }
         os_ << ")\n";
     }
 
     void visit(ast::AncillaDecl& decl) {
         os_ << prefix_ << "|- Ancilla Decl(" << decl.id() << "[" << decl.size()
             << "]";
-        if (decl.is_dirty())
+        if (decl.is_dirty()) {
             os_ << ", dirty";
+        }
         os_ << ")\n";
     }
 
diff --git a/qasmtools/include/qasmtools/utils/angle.hpp b/qasmtools/include/qasmtools/utils/angle.hpp
index 314a8d7..929e784 100644
--- a/qasmtools/include/qasmtools/utils/angle.hpp
+++ b/qasmtools/include/qasmtools/utils/angle.hpp
@@ -66,16 +66,18 @@ class Angle {
 
   public:
     constexpr Angle(int n, int d) : value_(std::make_pair(n, d)) {
-        if (d == 0)
+        if (d == 0) {
             throw std::invalid_argument(
                 "Trying to construct angle with denominator 0");
+        }
 
         normalize();
     }
     constexpr Angle(fraction angle) : value_(angle) {
-        if (angle.second == 0)
+        if (angle.second == 0) {
             throw std::invalid_argument(
                 "Trying to construct angle with denominator 0");
+        }
 
         normalize();
     }
diff --git a/src/AffineState.cpp b/src/AffineState.cpp
index 110ab9c..f4a8713 100644
--- a/src/AffineState.cpp
+++ b/src/AffineState.cpp
@@ -61,8 +61,9 @@ std::vector<int> AffineState::A_col_nonzeros(int col) {
     std::vector<int> ones;
     ones.reserve(n_);
     for (int row = 0; row < n_; ++row) {
-        if (A_(row, col) == 1)
+        if (A_(row, col) == 1) {
             ones.push_back(row);
+        }
     }
     return ones;
 }
@@ -74,8 +75,9 @@ std::vector<int> AffineState::Q_nonzeros() {
     std::vector<int> ones;
     ones.reserve(r_ - 1);
     for (int row = 0; row < r_ - 1; ++row) {
-        if (Q_(row, r_ - 1) != 0)
+        if (Q_(row, r_ - 1) != 0) {
             ones.push_back(row);
+        }
     }
     return ones;
 }
@@ -87,8 +89,9 @@ std::vector<int> AffineState::A_row_nonzeros(int row) {
     std::vector<int> ones;
     ones.reserve(r_);
     for (int col = 0; col < r_; ++col) {
-        if (A_(row, col) != 0)
+        if (A_(row, col) != 0) {
             ones.push_back(col);
+        }
     }
     return ones;
 }
@@ -106,8 +109,9 @@ void AffineState::ReindexSubtColumn(int k, int c,
     // Applies the update Column k of A <--- Column k - Column c
     assert(c != k);
 
-    for (int row : col_c_nonzeros)
+    for (int row : col_c_nonzeros) {
         A_(row, k) ^= 1;
+    }
 
     // These three lines could potentially be optimized but I do not anticipate
     // a significant speedup, so leaving as is for clarity
@@ -164,8 +168,9 @@ void AffineState::FixFinalBit(int z) {
     int u = Q_(r_ - 1, r_ - 1) % 4;
 
     // Step 2:
-    for (int row : a_ones)
+    for (int row : a_ones) {
         A_(row, r_ - 1) = 0;
+    }
 
     for (int rowcol : q_ones) {
         Q_(rowcol, r_ - 1) = 0;
@@ -175,10 +180,12 @@ void AffineState::FixFinalBit(int z) {
 
     // Step 3:
     if (z == 1) {
-        for (int i : q_ones)
+        for (int i : q_ones) {
             Q_(i, i) = (Q_(i, i) + 2) % 4;
-        for (int row : a_ones)
+        }
+        for (int row : a_ones) {
             b_(row) ^= 1;
+        }
         phase_ = (phase_ + 2 * u) % 8;
     }
 
@@ -227,8 +234,9 @@ void AffineState::ZeroColumnElim(int c) {
         std::vector<int> col_ell_nonzeros = A_col_nonzeros(ell);
 
         for (int col : q_ones) {
-            if (col != ell)
+            if (col != ell) {
                 ReindexSubtColumn(col, ell, col_ell_nonzeros);
+            }
         }
 
         ReindexSwapColumns(ell);
@@ -240,10 +248,11 @@ int AffineState::piv_col(int row_number) {
     // Given a row number, return the index of the column j for in which that
     // row has a pivot, and return -1 otherwise.
     auto it = std::find(pivots_.begin(), pivots_.end(), row_number);
-    if (it != pivots_.end())
+    if (it != pivots_.end()) {
         return it - pivots_.begin();
-    else
+    } else {
         return -1;
+    }
 }
 
 // GATES:
@@ -280,8 +289,9 @@ void AffineState::H(int j) {
     b_(j) = 0;
 
     // Step 7:
-    if (c > -1)
+    if (c > -1) {
         ZeroColumnElim(c);
+    }
 }
 
 void AffineState::CZ(int j, int k) {
@@ -300,19 +310,22 @@ void AffineState::CZ(int j, int k) {
         Q_(jj, jj) = (Q_(jj, jj) + 2 * b_(k)) % 4;
     }
 
-    for (int kk : Ak_ones)
+    for (int kk : Ak_ones) {
         Q_(kk, kk) = (Q_(kk, kk) + 2 * b_(j)) % 4;
+    }
 
     phase_ = (phase_ + 4 * b_(j) * b_(k)) % 8;
 }
 
 void AffineState::CX(int j, int k) {
     int c = piv_col(k);
-    for (int col : A_row_nonzeros(j))
+    for (int col : A_row_nonzeros(j)) {
         A_(k, col) ^= 1;
+    }
     b_(k) ^= b_(j);
-    if (c != -1)
+    if (c != -1) {
         ReselectPrincipalRow(-1, c);
+    }
 }
 
 void AffineState::SWAP(int j, int k) {
@@ -321,10 +334,12 @@ void AffineState::SWAP(int j, int k) {
 
     auto it_j = std::find(pivots_.begin(), pivots_.end(), j);
     auto it_k = std::find(pivots_.begin(), pivots_.end(), k);
-    if (it_j != pivots_.end())
+    if (it_j != pivots_.end()) {
         *it_j = k;
-    if (it_k != pivots_.end())
+    }
+    if (it_k != pivots_.end()) {
         *it_k = j;
+    }
 }
 
 void AffineState::S_or_SDG(int j, bool dg) {
@@ -400,14 +415,16 @@ int AffineState::MeasureZ(int j, bool postselect, int postselected_outcome) {
 
 std::vector<int> AffineState::MeasureAll() const {
     vec_u_t x(r_);
-    for (int i = 0; i < r_; ++i)
+    for (int i = 0; i < r_; ++i) {
         x(i) = random_bit();
+    }
 
     vec_u_t tmp = ReduceMod2(A_.block(0, 0, n_, r_) * x + b_);
 
     std::vector<int> result(n_);
-    for (int i = 0; i < n_; ++i)
+    for (int i = 0; i < n_; ++i) {
         result[i] = tmp(i);
+    }
 
     return result;
 }
@@ -422,8 +439,9 @@ std::map<std::vector<int>, int> AffineState::Sample(int nreps) const {
 
 void AffineState::Reset(int j) {
     int tmp = MeasureZ(j);
-    if (tmp == 1)
+    if (tmp == 1) {
         X(j);
+    }
 }
 
 // Eigen::VectorXcd AffineState::to_ket() const {
diff --git a/unit_tests/tests/tests.cpp b/unit_tests/tests/tests.cpp
index 24b710c..47a4b2d 100644
--- a/unit_tests/tests/tests.cpp
+++ b/unit_tests/tests/tests.cpp
@@ -32,7 +32,7 @@ std::string random_qasm(int nq, bool measure) {
     }
 
     // Now add n^3 random gates
-    int ngates = std::pow(nq,3);
+    int ngates = std::pow(nq, 3);
     for (int gatenumber = 0; gatenumber < ngates; ++gatenumber) {
         int randno = random_integer(0, 8);
         std::string gate = gates[randno]; // Select random number
@@ -79,7 +79,7 @@ std::string random_identity(int nq) {
     std::string inverse{};
 
     // Now add some gates
-    int ngates = std::pow(nq,3);
+    int ngates = std::pow(nq, 3);
     for (int gatenumber = 0; gatenumber < ngates; ++gatenumber) {
         int randno = random_integer(0, 8);
         std::string gate = gates[randno];
@@ -131,7 +131,7 @@ get_random_circuits(int nmin, int nmax) {
 // We will use a bunch of random circuits. We can save time by only generating
 // them once
 const std::pair<std::vector<std::string>, std::vector<std::string>> circs =
-    get_random_circuits(1, 15); 
+    get_random_circuits(1, 15);
 const std::vector<std::string> circs_without = circs.first;
 const std::vector<std::string> circs_with = circs.second;
 } // namespace