Question

I have the following program called Scorecommandline:

int main (int argc, char *argv[]) {
    if (argc!=15) {
        usage();
        exit(1);
    }

    int iArray[14];
    int i = 0;
    while(1){
        if(scanf("%d",&iArray[i]) != 1){
        break;
        }
        i++;
        if(i == 14) {
        i = 0;
        }
    }

    int age = atoi(iArray[1]);
    int b_AF = atoi(iArray[2]);
    int b_ra = atoi(iArray[3]);
    int b_renal = atoi(iArray[4]);
    int b_treatedhyp = atoi(iArray[5]);
    int b_type2 = atoi(iArray[6]);
    double bmi = atof(iArray[7]);
    int ethrisk = atoi(iArray[8]);
    int fh_cvd = atoi(iArray[9]);
    double rati = atof(iArray[10]);
    double sbp = atof(iArray[11]);
    int smoke_cat = atoi(iArray[12]);
    int surv = atoi(iArray[13]);
    double town = atof(iArray[14]);

    double score = cvd_femal(age,b_AF,b_ra,b_renal,b_treatedhyp,b_type2,bmi,ethrisk,fh_cvd,rati,sbp,smoke_cat,surv,town,&error,errorBuf,sizeof(errorBuf));
    if (error) {
        printf("%s", errorBuf);
        exit(1);
    }
    printf("%f\n", score);
}

in which I have a .dat file intended to be used for the args in this program, however if I type:

cat testscandata.dat | ./ScorecommandLine

the program does not read the file in as the parameters for the program. How do I solve this?

Thanks

Answer 1

You are confusing two different ways of passing input into a program. You can pass arguments to main in a program by invoking the command from the command-line and listing the arguments. For example:

./ScoreCommandLine 1 2 3 4 5 6 7 8 9 10 11 12 13 14

These arguments will be passed into main through argv.

You can also pipe input into a program by sending in data through stdin by using pipes and redirection:

SomeCommand | ./ScoreCommandLine

This will take the output of SomeCommand and use that as the stdin stream in ScoreCommandLine. You can read it by using scanf, etc.

In your case, you should either rewrite the program so that you aren’t expecting all the arguments to be passed in through the command-line, or you should use the xargs utility to convert stdin into command-line arguments:

xargs ./ScoreCommandLine < testscandata.dat

Hope this helps!