diff options
| -rw-r--r-- | main1.c (renamed from main.c) | 2 | ||||
| -rw-r--r-- | main2.c | 71 |
2 files changed, 72 insertions, 1 deletions
@@ -3,7 +3,7 @@ #include <time.h> #include <math.h> -#define GEN_MAX 1000000 +#define GEN_MAX 1000000000 static int tenpow(int pow) { int base = 10; @@ -0,0 +1,71 @@ +#include <stdlib.h> +#include <stdio.h> +#include <time.h> +#include <math.h> + +#define GEN_MAX 1000000000 + +static int tenpow(int pow) { + int base = 10; + int ret = 1; + while (pow) { + if (pow & 0b1) + ret *= base; + base *= base; + pow >>= 1; + } + return ret; +} + +static char get_at_pos(unsigned int n, int pos) { + n /= tenpow(pos); + return n % 10; +} + +int main(int argc, char *argv[]) { + srand(time(NULL)); + int arr[10] = {0}; + unsigned int gen; + + int iters, pos; + if (argc == 3) { + iters = atoi(argv[1]); + pos = atoi(argv[2]); + if (!iters || !pos) goto fail; + } else { + fputs("Iterations: ", stdout); + if (!scanf("%i", &iters)) goto fail; + fputs("Position (10^N): ", stdout); + if (!scanf("%i", &pos)) goto fail; + } + + for (int _ = 0; _ < iters; ++_) { + gen = rand() % GEN_MAX; +#ifdef PRINT_GENERATED + printf("%i\n", gen); +#endif + switch (get_at_pos(gen, pos)) { + case 0: ++arr[0]; break; + case 1: ++arr[1]; break; + case 2: ++arr[2]; break; + case 3: ++arr[3]; break; + case 4: ++arr[4]; break; + case 5: ++arr[5]; break; + case 6: ++arr[6]; break; + case 7: ++arr[7]; break; + case 8: ++arr[8]; break; + case 9: ++arr[9]; break; + default: __builtin_unreachable(); + } + } + + printf("count of numbers at position %i:\n", pos); + for (int i = 0; i < 10; ++i) + printf("\t%i: %i\n", i, arr[i]); + + return EXIT_SUCCESS; +fail: + fputs("Input a valid number\n", stderr); + return EXIT_FAILURE; +} + |