foo.cc: In function 'void fft(cp*, int, int)':
foo.cc:24:23: warning: comparison of integer expressions of different signedness: 'unsigned int' and 'int' [-Wsign-compare]
   24 |     for(unsigned i=2;i<=len;i<<=1){
      |                      ~^~~~~
foo.cc:27:22: warning: comparison of integer expressions of different signedness: 'int' and 'unsigned int' [-Wsign-compare]
   27 |         for(int j=1;j<i>>1;j+=2)  w[j]=w[j-1]*g;
      |                     ~^~~~~
foo.cc:30:26: warning: comparison of integer expressions of different signedness: 'int' and 'unsigned int' [-Wsign-compare]
   30 |             for(int l=0;l<i>>1;l++){
      |                         ~^~~~~
foo.cc: In function 'void FFT(int*, int*, int, int, int*)':
foo.cc:50:18: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   50 |         int j=len-1&len-i;
      |               ~~~^~
foo.cc:54:18: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   54 |         int j=len-1&len-i;
      |               ~~~^~

Found 30 testcases.
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