写一段代码，判断gpu是否可用

以下是判断GPU是否可用的代码示例：

#include <stdio.h>
#include <cuda_runtime.h>

int main() {
int deviceCount;
cudaError_t error = cudaGetDeviceCount(&deviceCount);
if (error != cudaSuccess) {
printf("CUDA error: %s\n", cudaGetErrorString(error));
return 1;
}
if (deviceCount == ) {
printf("There is no available GPU device.\n");
return 1;
}
printf("There are %d available GPU devices.\n", deviceCount);
return ;
}