C++ Code Snippets
Stdin
cpp
std::string line;
while (std::getline(std::cin, line)) {
// line
}Read File Content
cpp
std::string getFileString(const std::string filename) {
std::ifstream ifs(filename);
return std::string((std::istreambuf_iterator<char>(ifs)),
(std::istreambuf_iterator<char>()));
}Timing
cpp
auto t1 = std::chrono::high_resolution_clock::now();
// func();
auto t2 = std::chrono::high_resolution_clock::now();
double totalSeconds =
std::chrono::duration_cast<std::chrono::duration<double>>(t2 - t1)
.count();Disk Usage
(linux only)
cpp
// just run exec("du -s")
uint64_t getDiskUsage(const std::string& path) {
uint64_t usedKB;
std::ifstream buffer("du -s " + path);
buffer >> usedKB;
buffer.close();
return usedKB;
}Memory Usage
Ref: Stackoverflow: How to get memory usage at runtime using C++?
cpp
#include <fstream>
#include <unistd.h>
struct MemoryInfo {
// kb
double rss;
double sharedMemory;
double privateMemory;
};
MemoryInfo getMemoryInfo() {
int tSize = 0, resident = 0, share = 0;
std::ifstream buffer("/proc/self/statm");
buffer >> tSize >> resident >> share;
buffer.close();
long pageSizeKB = sysconf(_SC_PAGE_SIZE) / 1024;
double rss = resident * pageSizeKB;
double sharedMem = share * pageSizeKB;
return MemoryInfo{
.rss = rss,
.sharedMemory = sharedMem,
.privateMemory = rss - sharedMem,
};
}Write Lines
cpp
void writeValues(const std::string& filename,
const std::vector<uint64_t>& values) {
std::ofstream fp;
fp.open(filename);
if (!fp) {
throw std::runtime_error(filename + " open error");
}
for (const auto& v : values) {
fp << v << std::endl;
}
}