Unicode C
Unicode C
Check if Integer Exists at JSON Path
Demonstrates how to get an integer value at a JSON path, and how to check to see if it exists.Chilkat Unicode C Downloads
#include <C_CkJsonObjectW.h>
void ChilkatSample(void)
{
BOOL success;
HCkJsonObjectW json;
const wchar_t *path;
int val;
BOOL wasFound;
success = FALSE;
json = CkJsonObjectW_Create();
// First build simple JSON..
CkJsonObjectW_UpdateInt(json,L"test.abc",100);
CkJsonObjectW_putEmitCompact(json,FALSE);
wprintf(L"%s\n",CkJsonObjectW_emit(json));
// This is our JSON:
// {
// "test": {
// "abc": 100,
// }
// }
path = L"test.notHere";
// The call to IntOf will return 0, because it's not present.
// But how do we know if it really was present, and the value was truly 0?
val = CkJsonObjectW_IntOf(json,path);
wprintf(L"val = %d\n",val);
// We cannot use LastMethodSuccess because LastMethodSuccess only applies
// to methods that:
// - return a string
// - return a new Chilkat object, binary bytes, or a date/time.
// - returns a boolean status where TRUE = success and FALSE = failed.
// - returns an integer where failure is defined by a return value less than zero.
// The IntOf method fits none of these requirements, and therefore the LastMethodSuccess
// is not a valid indicator..
wasFound = CkJsonObjectW_getLastMethodSuccess(json);
wprintf(L"wasFound = %d (not a valid indicator)\n",wasFound);
// Instead, if the returned value is 0, we can double-check to see if the member was truly there..
if (val == 0) {
wasFound = CkJsonObjectW_HasMember(json,path);
wprintf(L"wasFound = %d\n",wasFound);
if (wasFound == TRUE) {
wprintf(L"The value was present and is 0.\n");
}
else {
wprintf(L"no member is present at test.notHere\n");
}
}
else {
wprintf(L"val = %d\n",val);
}
// Alternatively, you could check to see if the member exists beforehand..
if (CkJsonObjectW_HasMember(json,path) == TRUE) {
wprintf(L"val = %d\n",CkJsonObjectW_IntOf(json,path));
}
else {
wprintf(L"no member at %s\n",path);
}
CkJsonObjectW_Dispose(json);
}