Instantly share code, notes, and snippets.

@doersino /inttostr.c
Last active Jan 10, 2017

Embed
What would you like to do?
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
char *inttostr_conventional(int n) {
char *s = (char*) malloc(sizeof(char) * 42);
sprintf(s, "%d", n);
return s;
}
char *inttostr_log(int n) {
int len;
if (n > 0) {
len = (int) floor(log10(n)) + 1;
} else if (n == 0) {
len = 1;
} else if (n < 0) {
len = (int) floor(log10(-n)) + 2;
}
len += 1;
char *s = (char*) malloc(sizeof(char) * len);
sprintf(s, "%i", n);
return s;
}
char *inttostr_magic(int n) {
int len = snprintf((char*) 0, 0, "%i", n) + 1;
char *s = (char*) malloc(sizeof(char) * len);
snprintf(s, len, "%i", n);
return s;
}
void inttostr_benchmark() {
char *s = (char*) 0;
for (int i = -1000000; i < 1000000; i++) {
s = inttostr_conventional(i); // => 0.365s
//s = inttostr_log(i); // => 0.379s
//s = inttostr_magic(i); // => 0.544s
}
}
int main() {
inttostr_benchmark();
printf("%s", inttostr_magic(42));
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment