grep C hello world

#include <stdio.h>

int main() {
    FILE *file;
    char line[100];

    file = fopen("file.txt", "r");

    while (fgets(line, sizeof(line), file)) {
        if (strstr(line, "hello world")) {
            printf("Found: %s", line);
        }
    }

    fclose(file);

    return 0;
}