diff --git a/src/kit/taosdemo/taosdemo.c b/src/kit/taosdemo/taosdemo.c
index b669c75b45a79766e018ebda05452aa002e804de..6ab0ad95a466fedd7066ac34048e9a7ff704787e 100644
--- a/src/kit/taosdemo/taosdemo.c
+++ b/src/kit/taosdemo/taosdemo.c
@@ -1213,7 +1213,6 @@ static void fetchResult(TAOS_RES *res, threadInfo* pThreadInfo) {
   }
 
   int   totalLen = 0;
-  char  temp[16000];
 
   // fetch the records row by row
   while((row = taos_fetch_row(res))) {
@@ -1224,6 +1223,7 @@ static void fetchResult(TAOS_RES *res, threadInfo* pThreadInfo) {
         memset(databuf, 0, 100*1024*1024);
     }
     num_rows++;
+    char temp[16000] = {0};
     int len = taos_print_row(temp, row, fields, num_fields);
     len += sprintf(temp + len, "\n");
     //printf("query result:%s\n", temp);
diff --git a/tests/examples/c/apitest.c b/tests/examples/c/apitest.c
index 44d9d0cee6b8971f8208ae55798ef5e07b50a2ca..0f24df0f4767fe1cdace072425768473ffcaa88f 100644
--- a/tests/examples/c/apitest.c
+++ b/tests/examples/c/apitest.c
@@ -86,7 +86,7 @@ static int print_result(TAOS_RES* res, int blockFetch) {
     }
   } else {
     while ((row = taos_fetch_row(res))) {
-      char temp[256];
+      char temp[256] = {0};
       taos_print_row(temp, row, fields, num_fields);
       puts(temp);
       nRows++;
@@ -391,10 +391,10 @@ void verify_prepare(TAOS* taos) {
   int         rows = 0;
   int         num_fields = taos_num_fields(result);
   TAOS_FIELD *fields = taos_fetch_fields(result);
-  char        temp[256];
 
   // fetch the records row by row
   while ((row = taos_fetch_row(result))) {
+    char temp[256] = {0};
     rows++;
     taos_print_row(temp, row, fields, num_fields);
     printf("%s\n", temp);
@@ -614,10 +614,10 @@ void verify_prepare2(TAOS* taos) {
   int         rows = 0;
   int         num_fields = taos_num_fields(result);
   TAOS_FIELD *fields = taos_fetch_fields(result);
-  char        temp[256];
 
   // fetch the records row by row
   while ((row = taos_fetch_row(result))) {
+    char temp[256] = {0};
     rows++;
     taos_print_row(temp, row, fields, num_fields);
     printf("%s\n", temp);
@@ -866,12 +866,10 @@ void verify_prepare3(TAOS* taos) {
   int         rows = 0;
   int         num_fields = taos_num_fields(result);
   TAOS_FIELD *fields = taos_fetch_fields(result);
-  char        temp[256] = {0};
 
   // fetch the records row by row
   while ((row = taos_fetch_row(result))) {
-    memset(temp, 0, sizeof(temp)/sizeof(temp[0]));
-
+    char temp[256] = {0};
     rows++;
     taos_print_row(temp, row, fields, num_fields);
     printf("%s\n", temp);
diff --git a/tests/examples/c/demo.c b/tests/examples/c/demo.c
index 0b1cd7b5d2d304a89656c98e88b2a620e16ae5a1..f8c69d0043591afa8f5e32e80bd35e9413e60e76 100644
--- a/tests/examples/c/demo.c
+++ b/tests/examples/c/demo.c
@@ -116,12 +116,12 @@ void Test(TAOS *taos, char *qstr, int index)  {
   int         rows = 0;
   int         num_fields = taos_field_count(result);
   TAOS_FIELD *fields = taos_fetch_fields(result);
-  char        temp[1024];
 
   printf("num_fields = %d\n", num_fields);
   printf("select * from table, result:\n");
   // fetch the records row by row
   while ((row = taos_fetch_row(result))) {
+    char temp[1024] = {0};
     rows++;
     taos_print_row(temp, row, fields, num_fields);
     printf("%s\n", temp);
diff --git a/tests/examples/c/prepare.c b/tests/examples/c/prepare.c
index 13d71beea6156aa32677c20ccc2d222d28826b24..723b340a923c0bf326599e8090f8c6142a249053 100644
--- a/tests/examples/c/prepare.c
+++ b/tests/examples/c/prepare.c
@@ -184,10 +184,10 @@ int main(int argc, char *argv[])
   int         rows = 0;
   int         num_fields = taos_num_fields(result);
   TAOS_FIELD *fields = taos_fetch_fields(result);
-  char        temp[256];
 
   // fetch the records row by row
   while ((row = taos_fetch_row(result))) {
+    char temp[256] = {0};
     rows++;
     taos_print_row(temp, row, fields, num_fields);
     printf("%s\n", temp);
diff --git a/tests/examples/c/subscribe.c b/tests/examples/c/subscribe.c
index 1d3533fa5ee89f7425a9b0563e738b4e0703e6c8..ad12f0e7a55b0f471f249f92f30cf659c94586a5 100644
--- a/tests/examples/c/subscribe.c
+++ b/tests/examples/c/subscribe.c
@@ -14,8 +14,6 @@ void print_result(TAOS_RES* res, int blockFetch) {
   int         num_fields = taos_num_fields(res);
   TAOS_FIELD* fields = taos_fetch_fields(res);
   int         nRows = 0;
-  char        buf[4096];
-
   
   if (blockFetch) {
     nRows = taos_fetch_block(res, &row);
@@ -25,6 +23,7 @@ void print_result(TAOS_RES* res, int blockFetch) {
     //}
   } else {
     while ((row = taos_fetch_row(res))) {
+      char buf[4096] = {0};
       taos_print_row(buf, row, fields, num_fields);
       puts(buf);
       nRows++;