Question

How to read from text file only numbers in C. Except spaces, symbols, enters and letters.

That’s how i am reading text:

unsigned char symb, symb1;

FileIn = fopen("InCode.txt","rt"); 
while (!feof(FileIn))
    {
       symb=getc(FileIn);
       symb1=symb;
       printf("%c",symb1);
     }

This is how it should work:

/* Data in the file: */
12hj2 3h23j1

/* Output: */
1223231

Answer 1

Try this :

        char symb ;
        unsigned char symb1;
        FILE *FileIn;
        FileIn = fopen("InCode.txt","rt"); // Haven't checked fopen failure
        while ((symb=getc(FileIn))!=EOF)
            {
               symb1= (unsigned char) symb;  
               if(symb1 >= '0' && symb1 <='9')
                 printf("%c",symb1);
             }

If symb is between 0 to 9 you print it . And discard all other characters as you mentioned space, newline, alphabats (lower & upper) , any other symbols .