如何解决字符数组C
我尝试写implementation中的Weasel Program。我已经编译了三个版本,它们的名称完全相同,分别为“ weasel.exe”,“ weasel2.exe”和“ weasel3.exe”。 “ weasel.exe”产生预期的输出,
Gen 0: YPSZNcwpSDUMLYKRIKNSEOJCERIL
Gen 10: YPSZNcwpSDUMLYKRIKNSE JCERIL
Gen 92: YPSZNCKPSDUMLYKRIKNSE JCERIL
Gen 129: YPSZNCKPSDUMLYKRIKNSE JCEREL
Gen 240: YPSZICKPSDUMLYKRIKNSE JCEREL
Gen 388: YPSZICKPSDTMLYKRIKNSE JCEREL
Gen 570: YPSZICKPSDTMLYKRIKNSE JEEREL
Gen 634: YPSZICKPSDTMLYKRIKN E JEEREL
Gen 1102: YPSZICKPSDTMLSKRIKN E JEEREL
Gen 1185: YPSZICKPYDTMLSKRIKN E JEEREL
Gen 1223: YESZICKPYDTMLSKRIKN E JEEREL
Gen 1491: YESZICKPYITMLSKRIKN E JEEREL
Gen 1613: YESZICKPYITMISKRIKN E JEEREL
Gen 1627: YETZICKPYITMISKRIKN E JEEREL
Gen 1750: YETZICKPYITMISKRIKN E WEEREL
Gen 1855: YETZICKPJITMISKRIKN E WEEREL
Gen 2461: METZICKPJITMISKRIKN E WEEREL
Gen 2536: METZICKPJITMIS RIKN E WEEREL
Gen 2876: METZICKPJITMIS JIKN E WEEREL
Gen 3354: METZICKPJITMIS JIKN E WEAREL
Gen 3668: METZICKPJITMIS JIKN E WEASEL
Gen 3837: METZINKPJITMIS JIKN E WEASEL
Gen 3938: METZINKP ITMIS JIKN E WEASEL
Gen 4147: METHINKP ITMIS JIKN E WEASEL
Gen 4314: METHINKP ITMIS JIKE E WEASEL
Gen 4803: METHINKP ITMIS JIKE A WEASEL
Gen 5441: METHINKP ITMIS LIKE A WEASEL
Gen 6090: METHINKS ITMIS LIKE A WEASEL
Gen 7712: METHINKS IT IS LIKE A WEASEL
但是“ weasel2.exe”会产生这种情况
Gen 896: CB FNEOJWT WAVACDESTKWELIEF/c PnW~lcÏ
Gen 897: CB FNEOJWT WAVACDESTKWELIEF
Gen 981: CP FNEOJWT WAVACDESTKWELIEF
Gen 1014: CP FNEOJWT WAVLCDESTKWELIEFOWSE'•&E
Gen 1015: CP FNEOJWT WAVLCDESTKWELIEF
Gen 1087: CP FNEOJWT WAVLCDESTKWELSEF/c PnW~lcÏ
,在数组末尾还有其他不需要的字符。在某些世代中,这包括看起来像我的PATH环境变量的部分。根据我对其他SO问题的了解,这是因为数组末尾没有“ \ 0”字符,但是当我添加
[Line 75] offspring[i][28] = '\0';
对于后代分配循环,程序因内存访问冲突而崩溃。甚至可以写入的最低索引是8。“ weasel2.exe”将永远运行,并且尽管某些字符确实与weasel字符串匹配,但其他字符仍会无限期更改,即使它们确实设法“演变”为右侧字符。每次“ weasel3.exe”均因内存访问冲突而崩溃。编译时收到以下警告:
weasel2.c:85:警告:来自不兼容指针类型的赋值
weasel2.c:89:警告:来自不兼容指针类型的分配
但据我所知,这不是问题的原因(但我也可能错了)。
是什么原因造成的?为什么行为仅在编译之间有所不同,而对每个程序的测试却没有变化?
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
int randomNumber(int high) {
return rand() % high;
}
int generateOffspring(char* currentGen,int currentLen,char* letters,char** offspring,unsigned long children,int probability) {
for (unsigned int i = 0; i < children; i++) {
for (unsigned int c = 0; c < currentLen; c++) {
if (randomNumber(probability) < 1) {
offspring[i][c] = letters[randomNumber(27)];
}
else {
offspring[i][c] = currentGen[c];
}
}
}
return 0;
}
int findLeastdistance(char* string,char** strings,int len,int count) {
unsigned int matches = 0;
unsigned int bestMatches = 0;
unsigned int bestMatch = 0;
for (unsigned int i = 0; i < count; i++) {
for (unsigned int c = 0; c < len; c++) {
if (string[c] == strings[i][c]) {
matches++;
}
}
if (matches > bestMatches) {
bestMatches = matches;
bestMatch = i;
}
matches = 0;
}
return bestMatch;
}
int main(int argc,char *argv[]) {
system("PAUSE");
time_t t;
srand((unsigned)time(&t));
unsigned int probability;
if (argc == 2) {
probability = (int)argv[1];
}
else {
probability = 10000;
}
unsigned int children = 100;
char letters[] = "ABCDEFGHIJKLMnopQRSTUVWXYZ ";
char target[] = "METHINKS IT IS LIKE A WEASEL";
char currentGen[29];
for (unsigned int i = 0; i < 29; i++) {
currentGen[i] = letters[randomNumber(27)];
}
char** offspring[children];
for (unsigned int i = 0; i < children; i++) {
offspring[i] = malloc(29);
}
unsigned int bestMutation;
unsigned int counter = 0;
for (;;) {
generateOffspring(currentGen,28,letters,offspring,children,probability);
bestMutation = findLeastdistance(target,children);
if (strcmp(currentGen,offspring[bestMutation])) {
printf("Gen %d: %s\n",counter,offspring[bestMutation]);
}
strcpy(currentGen,offspring[bestMutation]);
if (!strcmp(currentGen,target)) {
break;
}
counter++;
}
for (unsigned int i = 0; i < children; i++) {
free(offspring[i]);
}
free(currentGen);
printf("\nEnd\n");
return 0;
}
解决方法
第一步,如下更改您的generateOffspring
循环:
for (unsigned int c = 0; c < currentLen - 1; c++) {
if (randomNumber(probability) < 1) {
offspring[i][c] = letters[randomNumber(27)];
}
else {
offspring[i][c] = currentGen[c];
}
}
offspring[i][currentLen - 1] = 0; // terminate offspring[i]
请记住,要存储N个字符长的字符串,则需要一个至少N + 1个元素长的数组来存储0终止符。
正如Antti Haapala指出的那样,您在currentGen
上也遇到了同样的问题,因此您需要将该循环更改为
for (unsigned int i = 0; i < 28; i++) {
currentGen[i] = letters[randomNumber(27)];
}
currentGen[28] = 0;
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