library/cpp/lwtrace/example4/lwtrace_example4.cpp


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#include <library/cpp/lwtrace/all.h>
 
#define LWTRACE_EXAMPLE_PROVIDER(PROBE, EVENT, GROUPS, TYPES, NAMES)     \
    PROBE(BackTrack, GROUPS(), TYPES(NLWTrace::TSymbol), NAMES("frame")) \
    /**/ 
 
LWTRACE_DECLARE_PROVIDER(LWTRACE_EXAMPLE_PROVIDER) 
LWTRACE_DEFINE_PROVIDER(LWTRACE_EXAMPLE_PROVIDER) 
 
LWTRACE_USING(LWTRACE_EXAMPLE_PROVIDER);

#define MY_BACKTRACK() LWPROBE(BackTrack, LWTRACE_LOCATION_SYMBOL)

void InitLWTrace() { 
    NLWTrace::StartLwtraceFromEnv(); 
} 
 
long double Fact(int n) {
    MY_BACKTRACK();
    if (n < 0) { 
        MY_BACKTRACK();
        ythrow yexception() << "N! is undefined for negative N (" << n << ")"; 
    } 
    double result = 1; 
    for (; n > 1; --n) { 
        MY_BACKTRACK();
        result *= n; 
    } 
    MY_BACKTRACK();
    return result; 
} 
 
void FactorialCalculator() { 
    MY_BACKTRACK();
    i32 n; 
    Cout << "Enter a number: "; 
    TString str;
    Cin >> n; 
    double factN = Fact(n); 
    Cout << n << "! = " << factN << Endl << Endl; 
} 
 
int main() { 
    InitLWTrace(); 
    MY_BACKTRACK();
    FactorialCalculator(); 
    MY_BACKTRACK();
    return 0; 
}