Compilare: user.c: In function ‘main’: user.c:10:8: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(input, "%d", &N); ^ user.c:11:8: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(input, "%d", &M); ^ user.c:18:10: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(input, "%d", &v[i][j]); ^ user.c:64:19: warning: ‘index_col’ may be used uninitialized in this function [-Wmaybe-uninitialized] v[i][index_col] *= -1; ^ user.c:22:19: warning: ‘index_lin’ may be used uninitialized in this function [-Wmaybe-uninitialized] int min_lin = 0, index_lin, index_col, min_col = 0, s; ^