Fix improper format specifier in printf

%d in format string requires 'int' but the argument type is 'unsigned int'.
diff --git a/src/jsontestrunner/main.cpp b/src/jsontestrunner/main.cpp
index 7105b39..54ca302 100644
--- a/src/jsontestrunner/main.cpp
+++ b/src/jsontestrunner/main.cpp
@@ -106,9 +106,9 @@
     for (Json::ArrayIndex index = 0; index < size; ++index) {
       static char buffer[16];
 #if defined(_MSC_VER) && defined(__STDC_SECURE_LIB__)
-      sprintf_s(buffer, sizeof(buffer), "[%d]", index);
+      sprintf_s(buffer, sizeof(buffer), "[%u]", index);
 #else
-      snprintf(buffer, sizeof(buffer), "[%d]", index);
+      snprintf(buffer, sizeof(buffer), "[%u]", index);
 #endif
       printValueTree(fout, value[index], path + buffer);
     }
diff --git a/src/test_lib_json/jsontest.cpp b/src/test_lib_json/jsontest.cpp
index 7ca58c3..ce23800 100644
--- a/src/test_lib_json/jsontest.cpp
+++ b/src/test_lib_json/jsontest.cpp
@@ -165,7 +165,7 @@
     const Failure& failure = *it;
     JSONCPP_STRING indent(failure.nestingLevel_ * 2, ' ');
     if (failure.file_) {
-      printf("%s%s(%d): ", indent.c_str(), failure.file_, failure.line_);
+      printf("%s%s(%u): ", indent.c_str(), failure.file_, failure.line_);
     }
     if (!failure.expr_.empty()) {
       printf("%s\n", failure.expr_.c_str());
@@ -281,7 +281,7 @@
 
   if (failures.empty()) {
     if (printSummary) {
-      printf("All %d tests passed\n", count);
+      printf("All %u tests passed\n", count);
     }
     return true;
   } else {
@@ -293,7 +293,7 @@
     if (printSummary) {
       unsigned int failedCount = static_cast<unsigned int>(failures.size());
       unsigned int passedCount = count - failedCount;
-      printf("%d/%d tests passed (%d failure(s))\n", passedCount, count,
+      printf("%u/%u tests passed (%u failure(s))\n", passedCount, count,
              failedCount);
     }
     return false;