C / XCode：sh：./child：没有这样的文件或目录。 命令在终端中运行，但不在XCode中运行

Question

So I have a child.c file and I want to compile and run it in my main.c file using the system() function of stdlib.h.

child.c:

#include<stdio.h>
int main(){
printf("I am the child\n");
return 0;
}

main.c:

#include <stdio.h>
#include <stdlib.h>

int main() {
    system("cd ~/Desktop/HW3/HW3");
    system("gcc -o child child.c");
    system("./child");
    return 0;
}

everything worked fine when I compile and run main.c in terminal using the following command

abcs-mbp:HW3 abc$ cd
abcs-mbp:~ abc$ cd ~/Desktop/HW3/HW3
abcs-mbp:HW3 abc$ gcc -o main main.c
abcs-mbp:HW3 abc$ ./main

and it ran child.c and printed the following:

I am the child

but when I tried to run the exact same main.c in XCode, XCode gave me the following error:

clang: error: no such file or directory: 'child.c'
clang: error: no input files
sh: ./child: No such file or directory

anybody know why this is happening? I think it has something to do with path, but how can I tell XCode the path of child.c and then tell it to compile child.c?

I also tried

 system("cd ~/Desktop/HW3/HW3");
 system("gcc -o child child.c");
 system("./child");

and

system("/Users/vqianxiao/Desktop/HW3/HW3/ gcc -o child child.c");

but nothing seems to work... any help is appreciated!

Answer 1

the reason that it does not work is a combination of things

1) each 'system' call is run in a separate shell instance, 
   so the second 'system' call 
   starts from the directory where the main program is running.

2) things do down from there

a suggested fix:

system("cd ~/Desktop/HW3/HW3; && gcc -o child child.c; && ./child;");

notice, all one system call, terminators at end of commands, and linked by && so one command must be successful to continue on to the next command