diff --git a/src/api/baseapi.cpp b/src/api/baseapi.cpp
index 9546b227..bcba45c0 100644
--- a/src/api/baseapi.cpp
+++ b/src/api/baseapi.cpp
@@ -119,8 +119,6 @@ static const char *kInputFile = "noname.tif";
  * Temp file used for storing current parameters before applying retry values.
  */
 static const char *kOldVarsFile = "failed_vars.txt";
-/** Max string length of an int.  */
-const int kMaxIntSize = 22;
 
 #ifndef DISABLED_LEGACY_ENGINE
 static const char kUnknownFontName[] = "UnknownFont";
@@ -1063,9 +1061,8 @@ bool TessBaseAPI::ProcessPagesMultipageTiff(const l_uint8 *data, size_t size, co
       // Only print page number for multipage TIFF file.
       tprintf("Page %d\n", page + 1);
     }
-    char page_str[kMaxIntSize];
-    snprintf(page_str, kMaxIntSize - 1, "%d", page);
-    SetVariable("applybox_page", page_str);
+    auto page_string = std::to_string(page);
+    SetVariable("applybox_page", page_string.c_str());
     bool r = ProcessPage(pix, page, filename, retry_config, timeout_millisec, renderer);
     pixDestroy(&pix);
     if (!r) {
diff --git a/src/api/tesseractmain.cpp b/src/api/tesseractmain.cpp
index f28cb5c4..7cc33e0f 100644
--- a/src/api/tesseractmain.cpp
+++ b/src/api/tesseractmain.cpp
@@ -686,9 +686,8 @@ int main(int argc, char **argv) {
   FixPageSegMode(api, pagesegmode);
 
   if (dpi) {
-    char dpi_string[255];
-    snprintf(dpi_string, 254, "%d", dpi);
-    api.SetVariable("user_defined_dpi", dpi_string);
+    auto dpi_string = std::to_string(dpi);
+    api.SetVariable("user_defined_dpi", dpi_string.c_str());
   }
 
   int ret_val = EXIT_SUCCESS;
diff --git a/src/ccutil/params.cpp b/src/ccutil/params.cpp
index e1c6a7d6..c4e087f0 100644
--- a/src/ccutil/params.cpp
+++ b/src/ccutil/params.cpp
@@ -139,9 +139,7 @@ bool ParamUtils::GetParamAsString(const char *name, const ParamsVectors *member_
   // Look for the parameter among int parameters.
   auto *ip = FindParam<IntParam>(name, GlobalParams()->int_params, member_params->int_params);
   if (ip) {
-    char buf[128];
-    snprintf(buf, sizeof(buf), "%d", int32_t(*ip));
-    *value = buf;
+    *value = std::to_string(int32_t(*ip));
     return true;
   }
   // Look for the parameter among bool parameters.
@@ -157,7 +155,7 @@ bool ParamUtils::GetParamAsString(const char *name, const ParamsVectors *member_
     std::ostringstream stream;
     stream.imbue(std::locale::classic());
     stream << double(*dp);
-    *value = stream.str().c_str();
+    *value = stream.str();
     return true;
   }
   return false;
@@ -191,21 +189,20 @@ void ParamUtils::PrintParams(FILE *fp, const ParamsVectors *member_params) {
 
 // Resets all parameters back to default values;
 void ParamUtils::ResetToDefaults(ParamsVectors *member_params) {
-  int v, i;
   int num_iterations = (member_params == nullptr) ? 1 : 2;
-  for (v = 0; v < num_iterations; ++v) {
+  for (int v = 0; v < num_iterations; ++v) {
     ParamsVectors *vec = (v == 0) ? GlobalParams() : member_params;
-    for (i = 0; i < vec->int_params.size(); ++i) {
-      vec->int_params[i]->ResetToDefault();
+    for (auto &param : vec->int_params) {
+      param->ResetToDefault();
     }
-    for (i = 0; i < vec->bool_params.size(); ++i) {
-      vec->bool_params[i]->ResetToDefault();
+    for (auto &param : vec->bool_params) {
+      param->ResetToDefault();
     }
-    for (auto &string_param : vec->string_params) {
-      string_param->ResetToDefault();
+    for (auto &param : vec->string_params) {
+      param->ResetToDefault();
     }
-    for (auto &double_param : vec->double_params) {
-      double_param->ResetToDefault();
+    for (auto &param : vec->double_params) {
+      param->ResetToDefault();
     }
   }
 }
diff --git a/src/textord/tabvector.cpp b/src/textord/tabvector.cpp
index 483c0e62..cdafbd94 100644
--- a/src/textord/tabvector.cpp
+++ b/src/textord/tabvector.cpp
@@ -560,10 +560,9 @@ void TabVector::Display(ScrollView *tab_win) {
   tab_win->Pen(ScrollView::GREY);
   tab_win->Line(startpt_.x(), startpt_.y(), startpt_.x(), extended_ymin_);
   tab_win->Line(endpt_.x(), extended_ymax_, endpt_.x(), endpt_.y());
-  char score_buf[64];
-  snprintf(score_buf, sizeof(score_buf), "%d", percent_score_);
+  auto score_string = std::to_string(percent_score_);
   tab_win->TextAttributes("Times", 50, false, false, false);
-  tab_win->Text(startpt_.x(), startpt_.y(), score_buf);
+  tab_win->Text(startpt_.x(), startpt_.y(), score_string.c_str());
 }
 
 #endif
diff --git a/src/training/common/mastertrainer.cpp b/src/training/common/mastertrainer.cpp
index c39df732..fe12d070 100644
--- a/src/training/common/mastertrainer.cpp
+++ b/src/training/common/mastertrainer.cpp
@@ -545,7 +545,7 @@ void MasterTrainer::SetupFlatShapeTable(ShapeTable *shape_table) {
   int num_shapes = flat_shapes_.NumShapes();
   for (int s = 0; s < num_shapes; ++s) {
     int font = flat_shapes_.GetShape(s)[0].font_ids[0];
-    int f = 0;
+    unsigned f = 0;
     for (f = 0; f < active_fonts.size(); ++f) {
       if (active_fonts[f] == font) {
         break;
@@ -994,7 +994,7 @@ void MasterTrainer::ClusterShapes(int min_shapes, int max_shape_unichars, float
     }
     min_dist = kInfiniteDist;
     for (int s1 = 0; s1 < num_shapes; ++s1) {
-      for (int i = 0; i < shape_dists[s1].size(); ++i) {
+      for (unsigned i = 0; i < shape_dists[s1].size(); ++i) {
         if (shape_dists[s1][i].distance < min_dist) {
           min_dist = shape_dists[s1][i].distance;
           min_s1 = s1;
diff --git a/src/viewer/svutil.cpp b/src/viewer/svutil.cpp
index 184e96cc..e6482188 100644
--- a/src/viewer/svutil.cpp
+++ b/src/viewer/svutil.cpp
@@ -120,10 +120,9 @@ SVSemaphore::SVSemaphore() {
 #  ifdef _WIN32
   semaphore_ = CreateSemaphore(0, 0, 10, 0);
 #  elif defined(__APPLE__)
-  char name[50];
-  snprintf(name, sizeof(name), "%ld", random());
-  sem_unlink(name);
-  semaphore_ = sem_open(name, O_CREAT, S_IWUSR, 0);
+  auto name = std::to_string(random());
+  sem_unlink(name.c_str());
+  semaphore_ = sem_open(name.c_str(), O_CREAT, S_IWUSR, 0);
   if (semaphore_ == SEM_FAILED) {
     perror("sem_open");
   }
@@ -270,8 +269,7 @@ SVNetwork::SVNetwork(const char *hostname, int port) {
   buffer_ptr_ = nullptr;
 
   struct addrinfo *addr_info = nullptr;
-  char port_str[40];
-  snprintf(port_str, 40, "%d", port);
+  auto port_string = std::to_string(port);
 #  ifdef _WIN32
   // Initialize Winsock
   WSADATA wsaData;
@@ -281,7 +279,7 @@ SVNetwork::SVNetwork(const char *hostname, int port) {
   }
 #  endif // _WIN32
 
-  if (getaddrinfo(hostname, port_str, nullptr, &addr_info) != 0) {
+  if (getaddrinfo(hostname, port_string.c_str(), nullptr, &addr_info) != 0) {
     std::cerr << "Error resolving name for ScrollView host " << std::string(hostname) << ":" << port
               << std::endl;
 #  ifdef _WIN32
diff --git a/unittest/heap_test.cc b/unittest/heap_test.cc
index 4d7cd2ed..1aa31fa5 100644
--- a/unittest/heap_test.cc
+++ b/unittest/heap_test.cc
@@ -50,7 +50,7 @@ public:
     std::sort(v->begin(), v->end());
     // Check that we have increasing order.
     EXPECT_LT((*v)[0].key(), v->back().key());
-    for (int i = 0; i < v->size(); ++i) {
+    for (unsigned i = 0; i < v->size(); ++i) {
       EXPECT_EQ((*v)[i].key(), heap->PeekTop().key());
       // Indices don't necessarily match for equal keys, so don't test them.
       if (i + 1 < v->size() && (*v)[i + 1].key() == (*v)[i].key()) {