i new learner , want output fill truth array use strstr() in c. there 3 keyword groups in lists different size need compare. keywords group 1: foo1,foo2. stored in truth[0],truth[1]. keywords group 2: bar1,bar2,bar3,bar4.stored in truth[2] truth[5]. keywords group 3: baz1,baz2,baz3,baz4,....stored in truth[6] truth[k-1]. all members in truth array set mask number (like -1) @ beginning assuming input not have keywords. if input matches keyword in keyword group, element in group should set 1 , other elements in same keywords group need set 0. want check there @ 1 keyword each keyword group. for example: input:"bar1"; output:[-1,-1, 1,0,0,0, -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,....]; input:"foo1_baz5"; output:[1,0, -1,-1,-1,-1, 0,0,0,0,1,0,0,0,0,0,...]; input:"foo1_bar1_baz1"; output:[1,0, 1,0,0,0, 1,0,0,0,0,0,0,0,0,0,...]; input:"foo1_foo2"; output:"too many keywords". this code have worked far (let's total 100 keywor...