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paroj/strconv.cpp

Created March 7, 2017 12:59
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  1. paroj created this gist Mar 7, 2017.
    49 changes: 49 additions & 0 deletions strconv.cpp
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,49 @@
    #include <cstring>
    #include <cmath>
    #include <cstdio>
    #include <ctime>
    #include <cstdlib>
    #include <sstream>

    #define NITER 5000000

    int main() {
    const char* pi_s = " 3.14159265358979323846 "; // M_PI

    float f;
    clock_t t;

    f = atoi(pi_s);
    printf("test %f\n", f);

    t = clock();
    for(size_t i = 0; i < NITER; i++)
    f = atof(pi_s);
    printf("strtof %fs\n", float(clock() - t)/CLOCKS_PER_SEC);

    t = clock();
    for(size_t i = 0; i < NITER; i++)
    f = strtof(pi_s, NULL);
    printf("atof %fs \n", float(clock() - t)/CLOCKS_PER_SEC);

    t = clock();
    for(size_t i = 0; i < NITER; i++)
    sscanf(pi_s, "%f", &f);
    printf("sscanf %fs\n", float(clock() - t)/CLOCKS_PER_SEC);

    t = clock();
    std::stringstream ss;
    for(size_t i = 0; i < NITER; i++) {
    ss.str(pi_s);
    ss.clear();
    ss >> f;
    }
    printf("std::stringstream reuse %fs\n", float(clock() - t)/CLOCKS_PER_SEC);

    t = clock();
    for(size_t i = 0; i < NITER; i++)
    std::stringstream(pi_s) >> f;
    printf("std::stringstream %fs\n", float(clock() - t)/CLOCKS_PER_SEC);

    return 0;
    }