How to parse operations in c? - c

Question

I decided to refresh my C by wring a simple little program. I tried to read in from a file "myfile.txt", apply operations and print to stdout. The file contains one line:
2 + 3
the output I expect is:
5
but I found this to be much more complicated than I originally expected. At first I tried using getc() but kept getting segfaults, then I tried fscanf() there is no output from addition to stdin except the print statement that prints:
2 1556274040
Why is the output 2 1556274040? And is there a better way to try to apply operations read form a file, like some apply() function that I can use?
Here's my code:
int main()
{
int ans, num1, num2;
char oper;
FILE *pFile;
pFile = fopen("myfile.txt", "r");
if (pFile != NULL) {
fscanf(pFile, "%d", &num1);
fscanf(pFile, "%c", &oper);
fscanf(pFile, "%d", &num2);
printf ("%d %c %d", num1, oper, num2);
if (oper == '+') {
ans = num1 + num2;
printf(ans);
}
fclose(pFile);
}
return 0;
}

Answer 1

printf(ans);
Not a valid syntax to print an int variable.
Try this -
printf("%d\n",ans);
As you ask
you can use fgets instead of using fscanf to read contents of file but make sure you check their return.

Answer 2

Here's a possible solution...
#include <stdio.h>
int main() {
int ans, num1, num2;
char oper;
FILE *pFile;
pFile = fopen("myfile.txt", "r"); // might need to specify binary/text
if (pFile != NULL) {
// fscanf(pFile, "%d", &num1); need spaces in format specifier.
// fscanf(pFile, "%c", &oper);
// fscanf(pFile, "%d", &num2);
// one way to solve...
fscanf(pFile, "%d %c %d", &num1, &oper, &num2);
fclose(pFile); // stopping some errors
printf ("%d %c %d = ", num1, oper, num2);
} // end if
else
puts("fopen returned NULL");
if (oper == '+') {
ans = num1 + num2;
printf("%d",ans);
} // end if
return 0;
} // end main