How to print a substring in C - c

Question

simple C question here!
So I am trying to parse through a string lets say: 1234567W
#include <stdlib.h>
#include <string.h>
int main(int argc, char *argv[]) {
//pointer to open file
FILE *op;
//open file of first parameter and read it "r"
op = fopen("TestCases.txt", "r");
//make an array of 1000
char x[1000];
char y[1000];
//declare variable nums as integer
int nums;
//if file is not found then exit and give error
if (!op) {
perror("Failed to open file!\n");
exit(1);
}
else {
while (fgets(x, sizeof(x), op)) {
//pounter to get the first coordinate to W
char *p = strtok(x, "W");
//print the first 3 digits of the string
printf("%.4sd\n", p);
}
}
return 0;
My output so far shows: "123d" because of the "%.4sd" in the printf function.
I now need to get the next two numbers, "45". Is there a regex expression I can use that will allow me to get the next two digits of a string?
I am new to C, so I was thinking more like "%(ignore the first 4 characters)(print next 2 digits)(ignore the last two digits)"
input: pic
output: pic
Please let me know.
Thanks all.

Answer 1

printf("Next two: %.2s\n", p + 4); should work.
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
int main(int argc, char *argv[]) {
//pointer to open file
FILE *op;
//open file of first parameter and read it "r"
op = fopen("TestCases.txt", "r");
//make an array of 1000
char x[1000];
char y[1000];
//declare variable nums as integer
int nums;
//if file is not found then exit and give error
if (!op) {
perror("Failed to open file!\n");
exit(1);
}
else {
while (fgets(x, sizeof(x), op)) {
//pounter to get the first coordinate to W
char *p = strtok(x, "W");
//print the first 3 digits of the string
printf("%.4sd\n", p);
printf("Next two: %.2s\n", p + 4);
}
}
return 0;
}
Side note: I added a missing stdio.h include. Please turn on compiler warnings, since this error would've been caught by them.