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Diffstat (limited to 'main.c')
| -rw-r--r-- | main.c | 110 |
1 files changed, 110 insertions, 0 deletions
@@ -0,0 +1,110 @@ +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <math.h> + +#include "primes.h" +#define DEFAULT_SIZE 30 + +//powq(): square roots +unsigned long long powq(int number, int power) +{ +unsigned long long result = 1;//result int, 1 by default +if (!power){return 1;}//if to the power of 0, return 1 +while(power)//loop until all powers have been calculated + { + result *= number;//in the end result=number*number*number*etc until power is reached + --power;//--power since a power has been calculated + } +return result; +} + +void checkPrime(char s[], int length) +{ +//if (s[0] == '\0'){result[0] = 'E'; result[1] = '\0'; return;}//catch case of blank input +//if (s[0] == '0' && s[1] == '\0'){printf("0\t| 0\n"); result[0] = '0'; result[1] = '\0'; return;}//catch case of 0 input +if (s[0] == '\0'){printf("Error\n"); return;}//catch case of blank input +if (s[0] == '0' && s[1] == '\0'){printf("Error\n"); return;}//catch case of 0 input +if (s[0] == '1' && s[1] == '\0'){printf("We all know that 1 isn't a prime number\n"); return;}//catch case of 1 input + +int power = 0; //int to store the power. +while(s[power] != '\0'){++power;}//increment power for however many non-null chars in the string. +--power;//The correct power is actually one less than above returns + +int i = 0;//counter int +long input = 0;//where the converted int is stored +while (s[i] != '\0')//convert the string of decimal numbers into a long long int + { + if (s[i] >= '0' && s[i] <= '9'){input += ((s[i] - '0') * powq(10,power));}//integer = integer + ([char converted to number] * (10^[position of number in string])) + ++i; + --power;//Deincrement the power. E.g. ([charvalue]*(10^3))+([nextcharvalue]*(10^2)) etc + } + +double squareRoot = sqrt((double)input); +printf("Square root: %lf\n", squareRoot); + +i=0; +while(1) + { + if (primes[i] > (int)squareRoot){printf("%d is larger than %lf. Prime\n", primes[i], squareRoot); return;}//if the prime is larger than the integer part of the sqaure root, it is not a prime + if ((input % primes[i]) != 0) + { + printf("%ld / %d = %lf not round\n", input, primes[i], (double)input/primes[i]); + if (i > 998){printf("Out of primes. Good job\n"); exit(1);} + ++i;//move up to next prime + } + else + { + printf("%ld / %d = %ld round\n", input, primes[i], input/primes[i]); + printf("Round result, number is not prime\n"); + break; + } + + } + + +} + +int main(int argc, char *argv[]) +{ +char input[DEFAULT_SIZE];//input string is DEFAULT_SIZE in length + +if (!argv[1]){goto stdinMode;} + + if (argv[1]) + { + printf("Usage (stdin mode): %s\n", argv[0]); + printf("Ctrl+D to exit\n"); + printf("Determines if number is prime and shows working.\n"); + printf("Licence: GPLv3\n"); + return 0; + } + +stdinMode: ; +int i; +nextnum: i=0; +char *character = fgets(input, DEFAULT_SIZE, stdin); +if (!character){exit(0);}//exit if EOF (fgets() returns -1 on EOF or error) +character = strstr(input,"\n");//try to find the newline in the input so it can be overwritten +if (!character){printf("Input too long\n"); while(getchar() != '\n'); goto nextnum;}//if more than 40 chars were read, input was too long +character = '\0'; //overwrite newline with null char + +//strip out invalid chars from the input string +int j;//another counter variable +for (i=0; input[i] != '\0'; ++i) + { + if ((input[i] < '0')||(input[i] > '9'))//if input[i] is an invalid character + { + j=i; + while(input[j] != '\0'){input[j++] = input[j+1];}//shift all characters above left, overwriting the character + --i;//deincrement i, since the string was just shrunk by one and the one just above could indeed be a matching char + } + } + +checkPrime(input, DEFAULT_SIZE-1); + +goto nextnum; + +return 0; +} + |