#include int main() { FILE * fr; /* read from */ FILE * fw; /* write to */ int status; int n; fr = fopen("test.txt", "r"); fw = fopen("out.txt", "w"); do { status = fscanf(fr, "%d", &n); if (status != EOF) { fprintf(fw, "Square of %d is %d\n", n, n*n); } } while (status != EOF); fclose(fr); fclose(fw); return 0; }