linux - Csh script call C program,arguments issue -

this line csh script

./model2grd $model -d$nx/$ny/$nz -o$x0/$y0 -i$dx/$dy -l$layer -c$coverage -avel.dat -gvel.grd 

this part of model2grd.c

for (i = 2; < argc; i++) {     if (argv[i][0] == '-') {         switch (argv[i][1]) {             case 'g':                 grdfile = &argv[i][2];                 lgrd = true;                 break;             case 'c':                 cov = &argv[i][2];                 lcov = true;                 break;             case 'a':                 xyzfile = &argv[i][2];                 lxyz = true;                 break;             case 'd':                 sscanf(&argv[i][2],"%d/%d/%d",&nx,&ny,&nz);                 break;             case 'i':                 sscanf(&argv[i][2], "%lf/%lf", &dx, &dy);                 break;             case 'o':                 sscanf(&argv[i][2], "%lf/%lf", &xmin, &ymin);                 break;             case 'l':                 layer = atoi(&argv[i][2]);                 break;             case 'n':                 nan = (float)atof(&argv[i][2]);                 break;             case 'z':                 cvalue = (float)atof(&argv[i][2]);                 break;             case 'v':                 verbose = true;                 break;             default:                 break;         }     } } 

does mean takes d(nx,ny,nz),with o(xmin , ymin),with l layer , c coverage?are avel.dat , gvel.grd input files or not?

avel.dat , gvel.grd not input files. @ argument parsing again.

 switch (argv[i][1]) {         case 'g':             grdfile = &argv[i][2];             lgrd = true;             break; 

consider argument:

-gvel.grd

in plain english, switch examines second character of each argument. in case -gvel.grd argument, looks @ g. passing test, case statement derives address of character comes immediately after g within character string. in other words, v.

therefore, file name vel.grd. should able apply same logic rest of arguments follow same pattern.