Read integers AND characters from file line by line in C

Question

I have a txt file of this form:

11
10
BU
1U
0U
0U
...

I would like to read each digit/character one by one from the file in C. The first two rows contain 2 integers, the rest of the rows contain first a letter/integer and then a letter. I unfortunately do not know how to realize this since you can't know if what you read is an integer or a character.

Could someone help me with this?

Answer 1

Here is a minimal exaple on how to address every single character in your file and transforming into integer if one is met. I am sure you could try and adapt this code to your needs. The code in addition jumps newlines and EOF.

To better understand how this works have a look at the standard ASCII.

#include<stdio.h>


int main(){
  FILE * handle;
  handle = fopen("data.txt","r");
  char var;

  while(var!=EOF){
    var=fgetc(handle);
    if(var>47&&var<58){
      printf("Value: %d",var);
      printf(" Integer: %d \n",var-48);
    }
    else if(var!=10 && var!=-1){
      printf("Value: %d",var);
      printf(" Char or other: %c\n",var);
  
    }
  }
 
}

Output:

Value: 49 Integer: 1 

Value: 49 Integer: 1

Value: 49 Integer: 1

Value: 48 Integer: 0

Value: 66 Char or other: B

Value: 85 Char or other: U

Value: 49 Integer: 1

Value: 85 Char or other: U

Value: 48 Integer: 0

Value: 85 Char or other: U

Value: 48 Integer: 0

Value: 85 Char or other: U