Question

C programming language question.

Supposed that there is a txt file with content "AA101 ABC ADC 2019-11-24", I want to read the information by blank space.

When program read the file, I want the program only print out ABC and ADC.

Please show the code.

Answer 1

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CODE:

#include<stdio.h>
#include<stdlib.h>
main(){
   char c,*str;
   int index,flag;
   // to open a file we need a file pointer
   FILE *fp;
   // openinig the file f.txt you change f.txt to your filename.txt
   // r is the mode of the file i.e., to read the contents of file f
   fp=fopen("f.txt","r");
   do{
       // getting each character in the file
       c=fgetc(fp);
       // this is the memory allocation for the string we want to print
       str=(char *)malloc(100*sizeof(char));
       // index is the index for storing in the str
       index=0;
       // flag is used to check whether it has any non aplhabets
       flag=1;
       // this loop is for checking the string upto space or newline or End of file
       while(c!=' ' && c!=EOF && c!='\n'){
           // if the character in the file is not an alphabet then falg is zero
           if(!isalpha(c))
               flag=0;
           else
               str[index++]=c; //storing the aplhabet in the str and incrementing the index
           // it works as
           // str[index]=c;
           // index=index+1;  
           //getting next character int the file      
           c=fgetc(fp);  
       }
       //the last value of every string is \0 it means the string has ended
       str[index]='\0';
       // flag 1 says that it has only alphabets
       // index 0 means empty string so index should be not zero
       if(flag==1 && index!=0)
           printf("%s\n",str);
       // clearing the space created by the str for new string
       free(str);
      
   }while(c!=EOF);
}

Code(Screenshot):

File (f.txt):

Output: