knapsack.cpp:46:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
46 | main() {
| ^~~~
knapsack.cpp: In function 'int main()':
knapsack.cpp:49:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
49 | if(fopen("TASK.INP", "r")) freopen("TASK.INP", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:51:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
51 | freopen(TASK".INP", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:52:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
52 | freopen(TASK".OUT", "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~