From 145fe7f354cae90573d270cd53fdec22233456ff Mon Sep 17 00:00:00 2001
From: Nimrod Gileadi <nimrod@google.com>
Date: Thu, 23 Mar 2023 06:48:32 -0700
Subject: [PATCH] Declare loop variables inside for loop declaration where
 possible.

PiperOrigin-RevId: 518846098
Change-Id: Icdb2e5894bd80110552e29270472eeb242e6cf2c
---
 src/engine/engine_collision_convex.c |  10 +-
 src/engine/engine_collision_driver.c |  41 ++++----
 src/engine/engine_forward.c          |  10 +-
 src/engine/engine_io.c               |   6 +-
 src/engine/engine_solver.c           |   3 +-
 src/engine/engine_vfs.c              |   2 +-
 src/engine/engine_vis_visualize.c    |   6 +-
 src/render/glad/glad.c               |   4 +-
 src/ui/ui_main.c                     | 136 ++++++++++++++-------------
 9 files changed, 111 insertions(+), 107 deletions(-)

diff --git a/src/engine/engine_collision_convex.c b/src/engine/engine_collision_convex.c
index 1a9296e7..9886e6e3 100644
--- a/src/engine/engine_collision_convex.c
+++ b/src/engine/engine_collision_convex.c
@@ -517,7 +517,7 @@ typedef struct _mjtPrism mjtPrism;
 
 // ccd prism support function
 static void prism_support(const void *obj, const ccd_vec3_t *dir, ccd_vec3_t *vec) {
-  int i, istart, ibest;
+  int istart, ibest;
   mjtNum best, tmp;
   const mjtPrism* p = (const mjtPrism*)obj;
 
@@ -525,7 +525,7 @@ static void prism_support(const void *obj, const ccd_vec3_t *dir, ccd_vec3_t *ve
   istart = dir->v[2]<0 ? 0 : 3;
   ibest = istart;
   best = mju_dot3(p->v[istart], dir->v);
-  for (i=istart+1; i<istart+3; i++) {
+  for (int i=istart+1; i<istart+3; i++) {
     if ((tmp = mju_dot3(p->v[i], dir->v)) > best) {
       ibest = i;
       best = tmp;
@@ -584,7 +584,7 @@ int mjc_ConvexHField(const mjModel* m, const mjData* d,
   int hid = m->geom_dataid[g1];
   int nrow = m->hfield_nrow[hid];
   int ncol = m->hfield_ncol[hid];
-  int r, c, dr[2], cnt, rmin, rmax, cmin, cmax, nvert;
+  int dr[2], cnt, rmin, rmax, cmin, cmax, nvert;
   const float* data = m->hfield_data + m->hfield_adr[hid];
   mjtPrism prism;
 
@@ -710,9 +710,9 @@ int mjc_ConvexHField(const mjModel* m, const mjData* d,
 
   // process all prisms in sub-grid
   cnt = 0;
-  for (r=rmin; r<rmax; r++) {
+  for (int r=rmin; r<rmax; r++) {
     nvert = 0;
-    for (c=cmin; c<=cmax; c++) {
+    for (int c=cmin; c<=cmax; c++) {
       for (int i=0; i<2; i++) {
         // send vertex to prism constructor
         addVert(&nvert, &prism, dx*c-size1[0], dy*(r+dr[i])-size1[1],
diff --git a/src/engine/engine_collision_driver.c b/src/engine/engine_collision_driver.c
index 4ec9bb7e..7d8eddd9 100644
--- a/src/engine/engine_collision_driver.c
+++ b/src/engine/engine_collision_driver.c
@@ -664,7 +664,7 @@ int mj_broadphase(const mjModel* m, mjData* d, int* pair, int maxpair) {
   // find center of non-world geoms; return if none
   cnt = 0;
   mju_zero3(cen);
-  for (i=0; i<ngeom; i++) {
+  for (int i=0; i<ngeom; i++) {
     if (m->geom_bodyid[i]) {
       mju_addTo3(cen, d->geom_xpos+3*i);
       cnt++;
@@ -673,14 +673,14 @@ int mj_broadphase(const mjModel* m, mjData* d, int* pair, int maxpair) {
   if (cnt==0) {
     return npair;
   } else {
-    for (i=0; i<3; i++) {
+    for (int i=0; i<3; i++) {
       cen[i] /= cnt;
     }
   }
 
   // compute covariance
   mju_zero(cov, 9);
-  for (i=0; i<ngeom; i++) {
+  for (int i=0; i<ngeom; i++) {
     if (m->geom_bodyid[i]) {
       mju_sub3(dif, d->geom_xpos+3*i, cen);
       mjtNum D00 = dif[0]*dif[0];
@@ -700,7 +700,7 @@ int mj_broadphase(const mjModel* m, mjData* d, int* pair, int maxpair) {
       cov[8] += D22;
     }
   }
-  for (i=0; i<9; i++) {
+  for (int i=0; i<9; i++) {
     cov[i] /= cnt;
   }
 
@@ -713,7 +713,7 @@ int mj_broadphase(const mjModel* m, mjData* d, int* pair, int maxpair) {
 
   // construct body AABB for the aligned frame, count collidable
   int bufcnt = 0;
-  for (i=1; i<nbody; i++) {
+  for (int i=1; i<nbody; i++) {
     makeAABB(m, d, aabb+6*i, i, frame);
 
     if (can_collide(m, i)) {
@@ -734,7 +734,7 @@ int mj_broadphase(const mjModel* m, mjData* d, int* pair, int maxpair) {
 
   // init sortbuf with axis0
   j = 0;
-  for (i=1; i<nbody; i++) {
+  for (int i=1; i<nbody; i++) {
     // cannot colide
     if (!can_collide(m, i)) {
       continue;
@@ -758,10 +758,10 @@ int mj_broadphase(const mjModel* m, mjData* d, int* pair, int maxpair) {
 
   // sweep and prune
   cnt = 0;    // size of active list
-  for (i=0; i<2*bufcnt; i++) {
+  for (int i=0; i<2*bufcnt; i++) {
     // min value: collide with all in list, add
     if (!(sortbuf[i].body_ismax & 0x10000)) {
-      for (j=0; j<cnt; j++) {
+      for (int j=0; j<cnt; j++) {
         // get body ids: no need to mask ismax because activebuf entries never have the ismax bit,
         // and sortbuf[i].body_ismax is tested above
         b1 = activebuf[j].body_ismax;
@@ -797,7 +797,7 @@ int mj_broadphase(const mjModel* m, mjData* d, int* pair, int maxpair) {
     // max value: remove corresponding min value from list
     else {
       toremove = sortbuf[i].body_ismax & 0xFFFF;
-      for (j=0; j<cnt; j++) {
+      for (int j=0; j<cnt; j++) {
         if (activebuf[j].body_ismax==toremove) {
           if (j<cnt-1) {
             memmove(activebuf+j, activebuf+j+1, sizeof(mjtBroadphase)*(cnt-1-j));
@@ -921,14 +921,13 @@ void mj_collideGeoms(const mjModel* m, mjData* d, int g1, int g2, int flg_user,
   // remove repeated contacts in box-box
   if (type1==mjGEOM_BOX && type2==mjGEOM_BOX) {
     // use dim field to mark: -1: bad, 0: good
-    for (i=0; i<num; i++) {
+    for (int i=0; i<num; i++) {
       con[i].dim = 0;
     }
 
     // find bad
-    int j;
-    for (i=0; i<num-1; i++) {
-      for (j=i+1; j<num; j++) {
+    for (int i=0; i<num-1; i++) {
+      for (int j=i+1; j<num; j++) {
         if (con[i].pos[0]==con[j].pos[0] &&
             con[i].pos[1]==con[j].pos[1] &&
             con[i].pos[2]==con[j].pos[2]) {
@@ -940,7 +939,7 @@ void mj_collideGeoms(const mjModel* m, mjData* d, int g1, int g2, int flg_user,
 
     // consolidate good
     i = 0;
-    for (j=0; j<num; j++) {
+    for (int j=0; j<num; j++) {
       if (con[j].dim==0) {
         // different: copy
         if (i<j) {
@@ -963,7 +962,7 @@ void mj_collideGeoms(const mjModel* m, mjData* d, int g1, int g2, int flg_user,
       int gp = (m->geom_priority[g1]>m->geom_priority[g2] ? g1 : g2);
 
       // friction
-      for (i=0; i<3; i++) {
+      for (int i=0; i<3; i++) {
         friction[2*i] = m->geom_friction[3*gp+i];
       }
 
@@ -977,7 +976,7 @@ void mj_collideGeoms(const mjModel* m, mjData* d, int g1, int g2, int flg_user,
     // same priority
     else {
       // friction: max
-      for (i=0; i<3; i++) {
+      for (int i=0; i<3; i++) {
         friction[2*i] = mju_max(m->geom_friction[3*g1+i], m->geom_friction[3*g2+i]);
       }
 
@@ -994,14 +993,14 @@ void mj_collideGeoms(const mjModel* m, mjData* d, int g1, int g2, int flg_user,
 
       // reference standard: mix
       if (m->geom_solref[mjNREF*g1]>0 && m->geom_solref[mjNREF*g2]>0) {
-        for (i=0; i<mjNREF; i++) {
+        for (int i=0; i<mjNREF; i++) {
           solref[i] = mix*m->geom_solref[mjNREF*g1+i] + (1-mix)*m->geom_solref[mjNREF*g2+i];
         }
       }
 
       // reference direct: min
       else {
-        for (i=0; i<mjNREF; i++) {
+        for (int i=0; i<mjNREF; i++) {
           solref[i] = mju_min(m->geom_solref[mjNREF*g1+i], m->geom_solref[mjNREF*g2+i]);
         }
       }
@@ -1019,7 +1018,7 @@ void mj_collideGeoms(const mjModel* m, mjData* d, int g1, int g2, int flg_user,
   // set friction, solref, solimp: pair
   else {
     // friction
-    for (i=0; i<5; i++) {
+    for (int i=0; i<5; i++) {
       friction[i] = m->pair_friction[5*ipair+i];
     }
 
@@ -1031,12 +1030,12 @@ void mj_collideGeoms(const mjModel* m, mjData* d, int g1, int g2, int flg_user,
   }
 
   // clamp friction to mjMINMU
-  for (i=0; i<5; i++) {
+  for (int i=0; i<5; i++) {
     friction[i] = mju_max(mjMINMU, friction[i]);
   }
 
   // add contact returned by collision detector
-  for (i=0; i<num; i++) {
+  for (int i=0; i<num; i++) {
     // set contact data
     if (condim > 6 || condim < 1) {  // SHOULD NOT OCCUR
       mju_error("Invalid condim value: %d", i);
diff --git a/src/engine/engine_forward.c b/src/engine/engine_forward.c
index 9209d91a..018db034 100644
--- a/src/engine/engine_forward.c
+++ b/src/engine/engine_forward.c
@@ -544,20 +544,22 @@ static void mj_advance(const mjModel* m, mjData* d,
 
 // Euler integrator, semi-implicit in velocity, possibly skipping factorisation
 void mj_EulerSkip(const mjModel* m, mjData* d, int skipfactor) {
-  int i, nv = m->nv, nM = m->nM;
+  int nv = m->nv, nM = m->nM;
   mjMARKSTACK;
   mjtNum* qfrc = mj_stackAlloc(d, nv);
   mjtNum* qacc = mj_stackAlloc(d, nv);
 
   // check for dof damping
-  for (i=0; i<nv; i++) {
+  int dof_damping = 0;
+  for (int i=0; i<nv; i++) {
     if (m->dof_damping[i]>0) {
+      dof_damping = 1;
       break;
     }
   }
 
   // no damping: explicit velocity integration
-  if (i>=nv) {
+  if (!dof_damping) {
     mju_copy(qacc, d->qacc, nv);
   }
 
@@ -568,7 +570,7 @@ void mj_EulerSkip(const mjModel* m, mjData* d, int skipfactor) {
 
       // MhB = M + h*diag(B)
       mju_copy(MhB, d->qM, m->nM);
-      for (i=0; i<nv; i++) {
+      for (int i=0; i<nv; i++) {
         MhB[m->dof_Madr[i]] += m->opt.timestep * m->dof_damping[i];
       }
 
diff --git a/src/engine/engine_io.c b/src/engine/engine_io.c
index e0fb7372..9ed19509 100644
--- a/src/engine/engine_io.c
+++ b/src/engine/engine_io.c
@@ -622,7 +622,7 @@ void mj_saveModel(const mjModel* m, const char* filename, void* buffer, int buff
 // load model from binary MJB file
 //  if vfs is not NULL, look up file in vfs before reading from disk
 mjModel* mj_loadModel(const char* filename, const mjVFS* vfs) {
-  int i, header[4] = {0};
+  int header[4] = {0};
   int expected_header[4] = {ID, sizeof(mjtNum), getnint(), getnptr()};
   int info[2000];
   int ptrbuf = 0;
@@ -633,7 +633,7 @@ mjModel* mj_loadModel(const char* filename, const mjVFS* vfs) {
   const void* buffer = NULL;
   int buffer_sz = 0;
   if (vfs) {
-    i = mj_findFileVFS(vfs, filename);
+    int i = mj_findFileVFS(vfs, filename);
     if (i>=0) {
       buffer_sz = vfs->filesize[i];
       buffer = vfs->filedata[i];
@@ -660,7 +660,7 @@ mjModel* mj_loadModel(const char* filename, const mjVFS* vfs) {
   }
 
   // check header
-  for (i=0; i<4; i++) {
+  for (int i=0; i<4; i++) {
     if (header[i]!=expected_header[i]) {
       if (fp) {
         fclose(fp);
diff --git a/src/engine/engine_solver.c b/src/engine/engine_solver.c
index afa806b6..6ae66944 100644
--- a/src/engine/engine_solver.c
+++ b/src/engine/engine_solver.c
@@ -105,7 +105,7 @@ static void ARdiaginv(const mjModel* m, mjData* d, mjtNum* res, int flg_subR) {
 // extract diagonal block from AR, clamp diag to 1e-10 if flg_subR
 static void extractBlock(const mjModel* m, mjData* d, mjtNum* Ac,
                          int start, int n, int flg_subR) {
-  int k, nefc = d->nefc;
+  int nefc = d->nefc;
   const mjtNum *AR = d->efc_AR;
   const int *rownnz = d->efc_AR_rownnz, *rowadr = d->efc_AR_rowadr, *colind = d->efc_AR_colind;
 
@@ -123,6 +123,7 @@ static void extractBlock(const mjModel* m, mjData* d, mjtNum* Ac,
                 }
     */
     // assume full sub-matrix, find starting k: same for all rows
+    int k;
     for (k=0; k<rownnz[start]; k++) {
       if (colind[rowadr[start]+k]==start) {
         break;
diff --git a/src/engine/engine_vfs.c b/src/engine/engine_vfs.c
index 7b15fab9..f0f91945 100644
--- a/src/engine/engine_vfs.c
+++ b/src/engine/engine_vfs.c
@@ -45,7 +45,7 @@ static void vfs_strippath(char* newname, const char* oldname) {
   mju_strncpy(newname, oldname+i+1, mjMAXVFSNAME);
 
   // make lowercase
-  for (i=strlen(newname)-1; i>=0; i--) {
+  for (int i=strlen(newname)-1; i>=0; i--) {
     if (newname[i]>='A' && newname[i]<='Z') {
       newname[i] = (char)(((int)newname[i]) +'a' - 'A');
     }
diff --git a/src/engine/engine_vis_visualize.c b/src/engine/engine_vis_visualize.c
index d3b6df9d..92a4517f 100644
--- a/src/engine/engine_vis_visualize.c
+++ b/src/engine/engine_vis_visualize.c
@@ -1059,9 +1059,9 @@ void mjv_addGeoms(const mjModel* m, mjData* d, const mjvOption* vopt,
     }
 
     // get geom group and clamp
-    int j = mjMAX(0, mjMIN(mjNGROUP-1, m->geom_group[i]));
+    int geomgroup = mjMAX(0, mjMIN(mjNGROUP-1, m->geom_group[i]));
 
-    if (vopt->geomgroup[j]) {
+    if (vopt->geomgroup[geomgroup]) {
       START
 
       // construct geom
@@ -1116,7 +1116,7 @@ void mjv_addGeoms(const mjModel* m, mjData* d, const mjvOption* vopt,
         // re-center infinite plane
         if (m->geom_size[3*i]<=0 || m->geom_size[3*i+1]<=0) {
           // vec = headpos - geompos
-          for (j=0; j<3; j++) {
+          for (int j=0; j<3; j++) {
             vec[j] = 0.5*(scn->camera[0].pos[j] + scn->camera[1].pos[j]) - d->geom_xpos[3*i+j];
           }
 
diff --git a/src/render/glad/glad.c b/src/render/glad/glad.c
index 71028903..5987fc3a 100644
--- a/src/render/glad/glad.c
+++ b/src/render/glad/glad.c
@@ -1428,7 +1428,7 @@ static void mjGlad_find_coreGL(void) {
    * https://github.com/elmindreda/greg/blob/master/templates/greg.c.in#L176
    * https://github.com/glfw/glfw/blob/master/src/context.c#L36
    */
-  int i, major, minor;
+  int major, minor;
 
   const char* version;
   const char* prefixes[] = {
@@ -1441,7 +1441,7 @@ static void mjGlad_find_coreGL(void) {
   version = (const char*) glGetString(GL_VERSION);
   if (!version) return;
 
-  for (i = 0;  prefixes[i];  i++) {
+  for (int i = 0;  prefixes[i];  i++) {
     const size_t length = strlen(prefixes[i]);
     if (strncmp(version, prefixes[i], length) == 0) {
       version += length;
diff --git a/src/ui/ui_main.c b/src/ui/ui_main.c
index 7c69f780..ab494611 100644
--- a/src/ui/ui_main.c
+++ b/src/ui/ui_main.c
@@ -1656,7 +1656,6 @@ void mjui_update(int section, int item, const mjUI* ui,
   }
 
   // draw section(s)
-  int k;
   mjtNum sel;
   mjrRect r;
   char text[mjMAXUITEXT];
@@ -1776,7 +1775,7 @@ void mjui_update(int section, int item, const mjUI* ui,
         drawrectangle(r, rgbpane, rgbpane, con);
 
         // text lines
-        for (k=0; k<it->multi.nelem; k++) {
+        for (int k=0; k<it->multi.nelem; k++) {
           drawtext(it->multi.name[k],
                    r.left+g_texthor,
                    r.bottom+g_textver+(it->multi.nelem-k-1)*(con->charHeight+g_textver),
@@ -1809,35 +1808,37 @@ void mjui_update(int section, int item, const mjUI* ui,
         break;
 
       case mjITEM_CHECKINT:
-      case mjITEM_CHECKBYTE:
-        if (state) {
-          rgbdecor = ui->color.check;
+      case mjITEM_CHECKBYTE: {
+          if (state) {
+            rgbdecor = ui->color.check;
+          }
+
+          // get value according to type
+          int k;
+          if (it->type==mjITEM_CHECKINT) {
+            k = *(int*)it->pdata;
+          } else {
+            k = *(mjtByte*)it->pdata;
+          }
+
+          // filled or outline
+          if (k) {
+            drawrectangle(it->rect, rgbdecor, NULL, con);
+          } else {
+            drawrectangle(it->rect, rgbdecor, rgbpane, con);
+          }
+
+          // name
+          drawtext(it->name,
+                  it->rect.left+g_texthor,
+                  it->rect.bottom+g_textver,
+                  maxwidth, rgbfont, con);
+
+          // shortcut
+          if (ui->mousehelp && it->single.shortcut)
+            shortcuthelp(it->rect, it->single.modifier, it->single.shortcut,
+                        ui, con);
         }
-
-        // get value according to type
-        if (it->type==mjITEM_CHECKINT) {
-          k = *(int*)it->pdata;
-        } else {
-          k = *(mjtByte*)it->pdata;
-        }
-
-        // filled or outline
-        if (k) {
-          drawrectangle(it->rect, rgbdecor, NULL, con);
-        } else {
-          drawrectangle(it->rect, rgbdecor, rgbpane, con);
-        }
-
-        // name
-        drawtext(it->name,
-                 it->rect.left+g_texthor,
-                 it->rect.bottom+g_textver,
-                 maxwidth, rgbfont, con);
-
-        // shortcut
-        if (ui->mousehelp && it->single.shortcut)
-          shortcuthelp(it->rect, it->single.modifier, it->single.shortcut,
-                       ui, con);
         break;
 
       case mjITEM_RADIO:
@@ -1859,7 +1860,7 @@ void mjui_update(int section, int item, const mjUI* ui,
         drawrectangle(r, rgbdecor, NULL, con);
 
         // element names
-        for (k=0; k<it->multi.nelem; k++) {
+        for (int k=0; k<it->multi.nelem; k++) {
           r = radioelement(it, k, ui, con);
           drawtext(it->multi.name[k],
                    r.left+g_texthor,
@@ -1868,39 +1869,40 @@ void mjui_update(int section, int item, const mjUI* ui,
         }
         break;
 
-      case mjITEM_RADIOLINE:
-        if (state) {
-          rgbdecor = ui->color.radio;
-        }
+      case mjITEM_RADIOLINE: {
+          if (state) {
+            rgbdecor = ui->color.radio;
+          }
 
-        // name
-        drawtext(it->name,
-                 s->rcontent.left+g_itemside+g_texthor,
-                 it->rect.bottom+g_textver,
-                 g_label-2*g_texthor, rgbfont, con);
+          // name
+          drawtext(it->name,
+                  s->rcontent.left+g_itemside+g_texthor,
+                  it->rect.bottom+g_textver,
+                  g_label-2*g_texthor, rgbfont, con);
 
-        // outline
-        drawrectangle(it->rect, rgbdecor, rgbpane, con);
+          // outline
+          drawrectangle(it->rect, rgbdecor, rgbpane, con);
 
-        // make separators
-        makeradioline(it, con, sep);
+          // make separators
+          makeradioline(it, con, sep);
 
-        // fill selected
-        k = *(int*)it->pdata;
-        r = it->rect;
-        r.left += sep[k];
-        r.width = sep[k+1] - sep[k];
-        drawrectangle(r, rgbdecor, NULL, con);
-
-        // element names
-        for (k=0; k<it->multi.nelem; k++) {
-          // compute rectangle for element
+          // fill selected
+          int k = *(int*)it->pdata;
           r = it->rect;
           r.left += sep[k];
           r.width = sep[k+1] - sep[k];
+          drawrectangle(r, rgbdecor, NULL, con);
 
-          // draw centered
-          drawtextrect(r, it->multi.name[k], rgbfont, con);
+          // element names
+          for (int k=0; k<it->multi.nelem; k++) {
+            // compute rectangle for element
+            r = it->rect;
+            r.left += sep[k];
+            r.width = sep[k+1] - sep[k];
+
+            // draw centered
+            drawtextrect(r, it->multi.name[k], rgbfont, con);
+          }
         }
         break;
 
@@ -1959,7 +1961,7 @@ void mjui_update(int section, int item, const mjUI* ui,
           r.height = g_textver;
 
           // draw ticks
-          for (k=1; k<(int)it->slider.divisions; k++) {
+          for (int k=1; k<(int)it->slider.divisions; k++) {
             r.left = it->rect.left - r.width/2 +
                      it->rect.width*k/it->slider.divisions;
             drawrectangle(r, rgbpane, NULL, con);
@@ -2007,8 +2009,8 @@ void mjui_update(int section, int item, const mjUI* ui,
           }
 
           // show cursor
-          k = textwidth(ui->edittext + ui->editscroll, con,
-                        ui->editcursor - ui->editscroll);
+          int k = textwidth(ui->edittext + ui->editscroll, con,
+                            ui->editcursor - ui->editscroll);
           r.left = it->rect.left + g_texthor + k - SCL(1, con);
           r.width = 2*SCL(1, con);
           r.bottom = it->rect.bottom + g_textver/2;
@@ -2064,7 +2066,7 @@ void mjui_update(int section, int item, const mjUI* ui,
       drawrectangle(r, ui->color.select2, NULL, con);
 
       // hightlight row under mouse
-      k = findselect(it, ui, state, con);
+      int k = findselect(it, ui, state, con);
       if (k>=0) {
         mjrRect r1 = r;
         r1.bottom = r.bottom + (it->multi.nelem-1-k)*cellheight;
@@ -2073,7 +2075,7 @@ void mjui_update(int section, int item, const mjUI* ui,
       }
 
       // values
-      for (k=0; k<it->multi.nelem; k++) {
+      for (int k=0; k<it->multi.nelem; k++) {
         drawtext(it->multi.name[k],
                  r.left+g_texthor,
                  r.bottom+g_textver+(it->multi.nelem-1-k)*cellheight,
@@ -2223,7 +2225,7 @@ mjuiItem* mjui_event(mjUI* ui, mjuiState* state, const mjrContext* con) {
     else if (sect_cur>0 && item_cur<0) {
       // double-click: make all sections like this
       if (state->doubleclick) {
-        for (i=0; i<ui->nsect; i++) {
+        for (int i=0; i<ui->nsect; i++) {
           if (ui->sect[i].state<2 && ui->sect[sect_cur-1].state<2) {
             ui->sect[i].state = ui->sect[sect_cur-1].state;
           }
@@ -2445,7 +2447,7 @@ mjuiItem* mjui_event(mjUI* ui, mjuiState* state, const mjrContext* con) {
       case mjKEY_BACKSPACE:       // delete before cursor
         if (ui->editcursor>0) {
           // shift chars after cursor to the left
-          for (i=ui->editcursor; i<=strlen(ui->edittext); i++) {
+          for (int i=ui->editcursor; i<=strlen(ui->edittext); i++) {
             ui->edittext[i-1] = ui->edittext[i];
           }
 
@@ -2457,7 +2459,7 @@ mjuiItem* mjui_event(mjUI* ui, mjuiState* state, const mjrContext* con) {
       case mjKEY_DELETE:          // delete after cursor
         if (ui->editcursor<strlen(ui->edittext)) {
           // shift chars after cursor to the left
-          for (i=ui->editcursor; i<=strlen(ui->edittext); i++) {
+          for (int i=ui->editcursor; i<=strlen(ui->edittext); i++) {
             ui->edittext[i] = ui->edittext[i+1];
           }
         }
@@ -2467,7 +2469,7 @@ mjuiItem* mjui_event(mjUI* ui, mjuiState* state, const mjrContext* con) {
         key = validkey(key, strlen(ui->edittext), it_edit->type, state);
         if (key) {
           // shift chars after cursor to the right
-          for (i=strlen(ui->edittext); i>=ui->editcursor; i--) {
+          for (int i=strlen(ui->edittext); i>=ui->editcursor; i--) {
             ui->edittext[i+1] = ui->edittext[i];
           }
 
@@ -2494,7 +2496,7 @@ mjuiItem* mjui_event(mjUI* ui, mjuiState* state, const mjrContext* con) {
       for (int n=0; n<ui->nsect; n++)
         if (matchshortcut(state, ui->sect[n].modifier, ui->sect[n].shortcut)) {
           // collapse all
-          for (i=0; i<ui->nsect; i++) {
+          for (int i=0; i<ui->nsect; i++) {
             if (ui->sect[i].state<2) {
               ui->sect[i].state = 0;
             }
@@ -2516,7 +2518,7 @@ mjuiItem* mjui_event(mjUI* ui, mjuiState* state, const mjrContext* con) {
 
       // search item shortcuts
       for (int n=0; n<ui->nsect; n++) {
-        for (i=0; i<ui->sect[n].nitem; i++) {
+        for (int i=0; i<ui->sect[n].nitem; i++) {
           // get pointer to item
           it = ui->sect[n].item + i;;