ref: 28f4567ba615c4036c079021392825757ef2a008
dir: /sys/src/cmd/seq.c/
#include <u.h> #include <libc.h> double min = 1.0; double max = 0.0; double incr = 1.0; int constant = 0; int nsteps; char *format; void usage(void) { fprint(2, "usage: seq [-fformat] [-w] [first [incr]] last\n"); exits("usage"); } void buildfmt(void) { char *dp; int w, p, maxw, maxp; static char fmt[16]; char buf[32]; double val; format = "%g\n"; if(!constant) return; maxw = 0; maxp = 0; for(val = min; val <= max; val += incr){ sprint(buf, "%g", val); if(strchr(buf, 'e')!=0) return; dp = strchr(buf,'.'); w = dp==0? strlen(buf): dp-buf; p = dp==0? 0: strlen(strchr(buf,'.')+1); if(w>maxw) maxw = w; if(p>maxp) maxp = p; } if(maxp > 0) maxw += maxp+1; sprint(fmt,"%%%d.%df\n", maxw, maxp); format = fmt; } void main(int argc, char *argv[]){ int j, n; char buf[256], ffmt[4096]; double val; ARGBEGIN{ case 'w': constant++; break; case 'f': format = EARGF(usage()); if(format[strlen(format)-1] != '\n'){ sprint(ffmt, "%s\n", format); format = ffmt; } break; default: goto out; }ARGEND out: if(argc<1 || argc>3) usage(); max = atof(argv[argc-1]); if(argc > 1) min = atof(argv[0]); if(argc > 2) incr = atof(argv[1]); if(incr == 0){ fprint(2, "seq: zero increment\n"); exits("zero increment"); } if(!format) buildfmt(); if(incr > 0){ for(val = min; val <= max; val += incr){ n = sprint(buf, format, val); if(constant) for(j=0; buf[j]==' '; j++) buf[j] ='0'; write(1, buf, n); } }else{ for(val = min; val >= max; val += incr){ n = sprint(buf, format, val); if(constant) for(j=0; buf[j]==' '; j++) buf[j] ='0'; write(1, buf, n); } } exits(0); }