submatrix.cpp: In function 'int main()': submatrix.cpp:13: warning: format '%s' expects type 'char*', but argument 2 has type 'char (*)[101]' submatrix.cpp:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result submatrix.cpp:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result submatrix.cpp:11: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result submatrix.cpp:13: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result submatrix.cpp:10: warning: 'x1' may be used uninitialized in this function submatrix.cpp:10: warning: 'x2' may be used uninitialized in this function submatrix.cpp:10: warning: 'y1' may be used uninitialized in this function submatrix.cpp:10: warning: 'y2' may be used uninitialized in this function