strcmp不工作，所以即使strcmp中的两个字符串变得相等，程序也不会超出for循环

Question

Though word and s2 are same the if(strcmp) statement is not executed. Where is the mistake?? I checked the code for reading from a file and tried out "printf" to see whether word and s2 are the same or not and found that they become same after about 10 iterations and should break out at that point but the program executes till i is less than zero.

Please help. Thanks in advance. PS "words.txt" is the inbuilt dictionary file in the fedora operating system

#include<stdio.h>
#include<string.h>
int main(int argc,char *argv[])
{
     FILE *ptr;
     ptr=fopen("./words.txt","r");
     char word[40];
     char ch;
     int i=70,j=0;
     char s2[] = "2";
     while(i>0){
          while (ch!='\n') {
               ch=fgetc(ptr);
               word[j]=ch;
               j++;
          } 
          word[j]='\0';
          if(strcmp(s2,word) == 0){
             break;
          }
          j=0; 
          if(ch=='\n'){
              ch=fgetc(ptr);
              word[j]=ch;
              j++;        
          }
          i--;
     }
     fclose(ptr); 
     return 0;
 }

Answer 1

You are using a variable before initializing its value:

while (ch != '\n') {

Anything could happen since the initial value of ch is not known. However, the odds are high (255 out of 256 chances) that the expression is initially true. After it has entered the loop once, all is well.

For the loop to work as expected, do not store \\n in the buffer. Since s2 does not contain \\n , strcmp() will never match as long the the newline is stored in there.