我正在完成基于线性同余生成器 (LCG) 的密码程序的头文件。它接收两个 unsigned long 值（m 和 c）并使用这些值生成 LCG 结构。在我的 getA() 中，我试图让它将 temp 变量添加到 uPrimes 数组中（以防它不能减少到 1，因此在计算 p 时可以包含它）但我一直收到错误：“浮点异常（核心转储）”。如果我不尝试这样做，它将运行到完成，但不会按需要执行。在最新的迭代中，我尝试将 uPrimes 数组的第一个值分配为 1，一旦 while 循环完成，它会将 temp 的值分配给第一个值，结果相同。任何帮助将不胜感激！（我提前为不匹配的变量声明道歉，
/* Header guard prevents errors if header is included twice */
#ifndef LCG_H
#define LCG_H
#include <stdlib.h>
struct LinearCongruentialGenerator
{
unsigned long m; /* modulus */
unsigned long c; /* increment */
unsigned long a; /* multiplier */
unsigned long x; /* value in sequence */
};
/***************************************************************/
/* Initialize an LCG with modulus m and increment c. */
/* Calculate multiplier a such that: */
/* a = 1+2p, if 4 is a factor of m, otherwise, a = 1+p. */
/* p = (product of m’s unique prime factors). */
/* a < m */
/* Seed value x is same as increment c. */
/* If values are invalid for LCG, set all fields to zero. */
/***************************************************************/
struct LinearCongruentialGenerator makeLCG(unsigned long m, unsigned long c);
/* Update lcg and return next value in the sequence. */
unsigned long getNextRandomValue(struct LinearCongruentialGenerator* lcg);
unsigned long getA(unsigned long m);
int checkInput(unsigned long m, unsigned long c);
struct LinearCongruentialGenerator makeLCG(unsigned long m, unsigned long c)
{
struct LinearCongruentialGenerator lcg;
if(checkInput(m,c) && (getA(m)<m && getA(m)>0))
{
lcg.m = m;
lcg.c = c;
lcg.a = getA(m);
lcg.x = c;
} else
{
lcg.m = 0; lcg.c = 0;
lcg.a = 0; lcg.x = 0;
}
return lcg;
}
unsigned long getNextRandomValue(struct LinearCongruentialGenerator* lcg)
{
lcg->x = ((lcg->a*lcg->x)+lcg->c)%lcg->m;
return lcg->x;
}
unsigned long getA(unsigned long m)
{
unsigned long primes[15] = {2,3,5,7,11,13,17,19,23,29,31,37,41,43,47};
int uPrimes[63];
unsigned long temp = m; int y = 0; int p = 1;
int prev; int z; unsigned long a; int q = 1;
uPrimes[0] = 1;
while(y < 16)
{
if(temp % primes[y] == 0)
{
if(primes[y] != prev)
{
uPrimes[q] = primes[y];
prev = primes[y];
q++; y++;
printf("Unique Prime for %lu is: %d\n", m, uPrimes[q-1]);
} else temp = temp/primes[y];
} else y++;
}
uPrimes[0] = temp;
for(z = 0; z < q; z++)
{
p = p * uPrimes[z];
printf("P for %lu is %d\n", m, p);
}
if(m % 4 == 0){a = 1+(2*p);}
else a = 1+p;
if(a < m && a > 0){return a;}
else return 0;
}
int checkInput(unsigned long m, unsigned long c)
{
int x = 2;
if(c > m || c <= 0){return 0;}
else
{
while(x < c)
{
if(m % x == 0 && c % x == 0)
{return 0;}
else x++;
}
return 1;
}
}
#endif
这是给我的测试文件，用于验证我的头文件是否按需要工作：
#include <stdio.h>
#include "lcg.h"
/* Print LCG values along with a message */
void printLCG(struct LinearCongruentialGenerator* lcg, char* msg)
{
printf("%s (m=%lu,a=%lu,c=%lu,x=%lu)\n", msg, lcg->m, lcg->a, lcg->c, lcg->x);
}
/* Print message and n values generated by the LCG */
void testValues(struct LinearCongruentialGenerator* lcg, char* msg, int n)
{
int i;
printf("%s\n", msg);
for(i = 0; i < n; ++i)
{
unsigned long x = getNextRandomValue(lcg);
printf("%lu\n", x);
}
}
/* Create and test a few LCGs */
int main()
{
struct LinearCongruentialGenerator lcg1 = makeLCG(126,25);
struct LinearCongruentialGenerator lcg2 = makeLCG(38875,1234);
struct LinearCongruentialGenerator lcg3 = makeLCG(4611686018427387904,961168601842738797);
/* Some error cases */
struct LinearCongruentialGenerator lcg4 = makeLCG(4,3);
struct LinearCongruentialGenerator lcg5 = makeLCG(0,5);
struct LinearCongruentialGenerator lcg6 = makeLCG(5,0);
printLCG(&lcg1, "initialized lcg1");
printLCG(&lcg2, "initialized lcg2");
printLCG(&lcg3, "initialized lcg3");
printLCG(&lcg4, "initialized error test lcg4");
printLCG(&lcg5, "initialized error test lcg5");
printLCG(&lcg6, "initialized error test lcg6");
testValues(&lcg1, "test lcg1", 10);
testValues(&lcg2, "test lcg2", 10);
testValues(&lcg3, "test lcg3", 10);
printLCG(&lcg1, "lcg1 after first test");
printLCG(&lcg2, "lcg2 after first test");
printLCG(&lcg3, "lcg3 after first test");
testValues(&lcg1, "test lcg1 again", 20);
printLCG(&lcg1, "lcg1 after second test");
return 0;
}