Question

Create a program in C where pipes are used. The program's execution line should indicate the number of children and the elements of an array that will compute their sums. The number of children can only be 1, 2, or 3.

./myprogram 3 1 2 3 4 6 12 (3 indicates the number of children in the array)

Example for executing in linux terminal:Assuming parent has pid 5, child one has pid 6, child two has pid 7, and child three has pid 8. We would want to see the following output:

>>I am the parent with pid: 5 sending the array: 1,2,3,4,6,12.

>> I am the child with pid: 6 adding the array 1, 2 and sending the partial sum 3

>> I am the child with pid: 7 adding the array 3, 4 and sending the partial sum 7

>> I am the child with pid: 8adding the array 6, 12 and sending the partial sum 18

>> I am the parent with pid 5 receiving from child with pid 6 the partial sum of 3, for child with pid 7 the partial sum of 7, and for child with pid 8 the partial sum of 18, with a total sum of 28

Answer 1

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

int main(int argc, char *argv[])
{
int fd1,fd2,fd3;
fd1=fork();
fd2=fork();
fd3=fork();
int f[2],f1[2],f2[2],f3[2],f4[2],f5[2],val=0,val1=0,val2=0,val3=0,val4=0,val5=0;
pipe(f),pipe(f1),pipe(f2),pipe(f3),pipe(f4),pipe(f5);

if(atoi(argv[1])>3){
printf("Child processes exceeded!! Enter less than 3 childs");
exit(0);
}
else{
if(fd1>0 && fd2>0 && fd3>0){
printf("I am the parent with pId: %d",getpid());
printf(" sending the array: ");
for(int i=2;i<argc;i++){
printf("%d ",atoi(argv[i]));
}
close(f[1]);
close(f1[1]);
close(f2[1]);
close(f3[1]);
close(f4[1]);
close(f5[1]);
read(f[0],&val,sizeof(val));
read(f1[0],&val1,sizeof(val1));
read(f2[0],&val2,sizeof(val2));
read(f3[0],&val3,sizeof(val3));
read(f4[0],&val4,sizeof(val4));
read(f5[0],&val5,sizeof(val5));
printf("\nI am the parent with pid %d receiving from child with pid %d the partial sum of %d, for child with pid %d the partial sum of %d, and for child with pid %d the partial sum of: %d, with a total sum of: %d\n",getpid(),val,val1,val2,val3,val4,val5,val1+val3+val5);
close(f[0]);
close(f1[0]);
close(f2[0]);
close(f3[0]);
close(f4[0]);
close(f5[0]);
}
if(fd1==0 && fd2>0 && fd3>0){
close(f[0]);
close(f1[0]);
val=getpid();
printf("\nI am the child with pId: %d",getpid());
printf(" adding the array: %d, %d",atoi(argv[2]),atoi(argv[3]));
val1=atoi(argv[2])+atoi(argv[3]);
printf(" sending the partial sum: %d",atoi(argv[2])+atoi(argv[3]));
write(f[1],&val,sizeof(val));
write(f1[1],&val1,sizeof(val1));
close(f[1]);
close(f1[1]);
}
if(fd1>0 && fd2==0 && fd3>0){
close(f2[0]);
close(f3[0]);
val2=getpid();
printf("\nI am the child with pId: %d",getpid());
printf(" adding the array: %d, %d",atoi(argv[4]),atoi(argv[5]));
val3=atoi(argv[4])+atoi(argv[5]);
printf(" sending the partial sum: %d",atoi(argv[4])+atoi(argv[5]));
write(f2[1],&val2,sizeof(val2));
write(f3[1],&val3,sizeof(val3));
close(f2[1]);
close(f3[1]);
}
if(fd1>0 && fd2>0 && fd3==0){
close(f4[0]);
close(f5[0]);
val4=getpid();
printf("\nI am the child with pId: %d",getpid());
printf(" adding the array: %d, %d",atoi(argv[6]),atoi(argv[7]));
val5=atoi(argv[6])+atoi(argv[7]);
printf(" sending the partial sum: %d",atoi(argv[6])+atoi(argv[7]));
write(f4[1],&val4,sizeof(val4));
write(f5[1],&val5,sizeof(val5));
close(f4[1]);
close(f5[1]);
}
}
return(0);
}