我是编码的初学者,所以我可能在这里和那里都犯了很多菜鸟错误。我们在学校里完成了这项任务,目标是找出最长的单词,并将其与字符数一起打印出来。我已经走了很远,但是从现在开始,我很难找到问题所在。该程序大部分时间卡在迭代49、50、51和59上。我认为这是因为realloc对于longestWord变量返回NULL。
有什么想法可以解决这些问题?在此先感谢大家!
输入:
abc
abcde
abcdefghij
abcdefghij
abcdefghijklmnopq
abcdefghijklmnopq
abcdefghijklmnop
auf wiedersehen
预期输出:
17 characters in longest word: abcdefghijklmnopq
到目前为止,我的代码:
#include <stdio.h>
#include <stdlib.h>
//_________//
FILE* fptr;
int c;
int iteration=0; //Just to keep track
//___________Main____________//
int main()
{
fptr = fopen("C:\\....\\input", "r");
char *s;
char *longestWord;
int i=1, charCount=0;
s = (char*) malloc (sizeof(char));
longestWord = (char*) malloc (sizeof(char));
while((c=fgetc(fptr)) != EOF){
iteration++;
printf("Iteration %d\n",iteration);
if (isalpha(c)!=0 ){
s=realloc(s,i*sizeof(char));
s[i]=c;
i++;
}
else if(c==' ' || c =='\n'){
if(i>charCount){
charCount=i-1;
longestWord=realloc(longestWord,i*sizeof(char));
while(longestWord == NULL){
longestWord=realloc(longestWord,i*sizeof(char));
}
for(int t=0;t<i;t++){
*(longestWord+t)=*(s+t);
}
i=1;
}
else{
printf("*********Checkpoint 3***************\n"); //Checkpoint 3
i=1;
}
}
else{
printf("\n\n********Error, got to the else section of the program********\n\n");
}
}
printf("%d characters in the longest word: %s\n",charCount, longestWord);
free(s);
free(longestWord);
fclose(fptr);
return 0;
} //_____________END OF MAIN____________ //
这里是您所执行代码的更新版本。
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
int main()
{
FILE* fptr;
int c;
char *s;
char *longestWord;
int i=0;
fptr = fopen("input.txt", "r"); // TODO: validate if fptr is not NULL
// TODO: validate the return of mallocs
s = (char*) malloc (sizeof(char)); // allocates 1 element
longestWord = (char*) malloc(sizeof(char));
while((c=fgetc(fptr)) != EOF){
if (isalpha(c) != 0 ){
s=realloc(s, strlen(s)+1);
s[i]=c;
i++;
}
else if(c==' ' || c =='\n'){
s[i] = '\0';
// check if it is the longest
if(strlen(s) > strlen(longestWord)) {
longestWord = realloc(longestWord, strlen(s)+1);
strcpy(longestWord, s);
}
memset(s, '\0', strlen(s)+1);
i=0;
}
else{
printf("Weird character %c\n", c);
}
}
printf("%ld characters in the longest word: %s\n", strlen(longestWord), longestWord);
free(s);
free(longestWord);
fclose(fptr);
return 0;
}
请注意以下内容:
fopen
,malloc
,...等函数的返回值的验证;