how to pass a variable to command in c

Question

I've written a C program on Linux to calculate the perimeter (I've called the perimeter variable "p") of a square from its side length ("l"). Now I want to use Espeak, a speech synthesis program on Linux to speak the result. I've thought of using the "system" method.

For example, if I want to make Espeak speak "hello" inside my program I would do:

system("espeak -v it Hello");

Now how can I do with the perimeter?

system ("espeak -v it The perimeter is p");

doesn't work.

Probably just need to add quotes around the phrase so it is just one parameter. — Hogan, Dec 23 '14 at 16:14
possible duplicate of [pass parameter using system command](http://stackoverflow.com/questions/18014626/pass-parameter-using-system-command) — Paul Roub, Dec 23 '14 at 16:14
@skrrgwasme loved the "removed fluff" in the edit description. It made my... 10 mintues — bolov, Dec 23 '14 at 16:26

Iharob Al Asimi · Accepted Answer · 2014-12-23T16:21:44.127

3

You could build the command like in

char command[128];
snprintf(command, sizeof command, "espeak -v it The perimeter is %d", p);

if p is an integer, you should change the format specifier if the type of p is different.

edited Dec 23 '14 at 16:21

answered Dec 23 '14 at 16:16

Iharob Al Asimi

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close, but OP has a variable named `p` that needs to get embedded into the string. `"espeak -v it the perimeter is %s"` – Marc B Dec 23 '14 at 16:18
As an exercise for the reader, now make it pass "three hundred twenty". :-) – Lee Daniel Crocker Dec 23 '14 at 18:14

score -1 · Answer 2 · edited Dec 23 '14 at 16:38

-1

Thanks to all! I just solved with

#include<stdio.h>
int main()
{
    char command[128];
    int p=40;
    snprintf(command, sizeof(command), "espeak -v it  \"Il perimetro è %d\"",p);
    printf("%s\n",command);
    system(command);
}

edited Dec 23 '14 at 16:38

Iharob Al Asimi

52,653
6
59
97

answered Dec 23 '14 at 16:33

Jacquelyn.Marquardt

602
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how to pass a variable to command in c

2 Answers2