phầnc
Bài 36
#include "stdio.h"
main(){
int pid;
pid=fork();
if(pid!=0)
printf("
tien trinh cha ke thuc voi PID=%d,PPID=%d",getpid(),getppid());
else sleep(5);
printf("
tien trinh con tro thanh tien trinh bo vo voi PID=%d,PPID=%d
",getpid(),getppid());
}
Bài 37
#include "stdio.h"
main(){
int pid;
pid=fork();
if(pid!=0)
while(1) sleep(1000);
else exit(42);
}
BÀI 38
#include "stdio.h"
#include "sys/file.h"
#include "string.h"
int docmatran(int[10][10]);
int convert(char);
void luumatran(int[10][10],int);
void xuongdong(int);
void writeC(int,int);
main(){
char s[100];
int l1=0,l2=0,mtA[10][10],mtB[10][10],mtC[10][10],i,j,k;
printf("nhap file ma tran A:
");
l1=docmatran(mtA);
printf("nhap file ma tran B:
");
l2=docmatran(mtB);
for(i=1;i<=l1;i++)
for(j=1;j<=l2;j++){
mtC[i][j]=0;
for(k=1;k<=l1;k++){
mtC[i][j]=mtC[i][j]+mtA[i][k]*mtB[k][j];
}
}
printf("
ma tran tich A la :
");
for(i=1;i<=l1;i++){
for(j=1;j<=l1;j++)
printf("%d ",mtA[i][j]);
printf("
");
}
printf("
ma tran tich B la :
");
for(i=1;i<=l1;i++){
for(j=1;j<=l1;j++)
printf("%d ",mtB[i][j]);
printf("
");
}
printf("
ma tran tich C la :
");
for(i=1;i<=l1;i++){
for(j=1;j<=l1;j++)
printf("%d ",mtC[i][j]);
printf("
");
}
luumatran(mtC,l1);
}
int docmatran(int matran[10][10])
{
int fd,k=1,sg2=1,d[10][10],j=1,s1,s2;
char i[10],s[100];
printf("nhap vao file ma tran:");
fflush(stdin);
gets(s);
fd=open(s,O_RDONLY);
while (sg2!=0){
sg2=read(fd,i,1);
if(sg2!=0){
d[k][j]=0;
while(((int)i[0] != 32)&&((int)i[0] != 10))
{
d[k][j]=d[k][j]*10+convert(i[0]);
sg2=read(fd,i,1);
if((int)i[0]==32) j=j+1;
}
if(((int)i[0] == 10)){
k=k+1;
j=1;
}
}
}
k=k-1;
for(s1=1;s1<=k;s1++)
for(s2=1;s2<=k;s2++)
matran[s1][s2]=d[s1][s2];
return k;
close(fd);
}
int convert(char c){
return (int)c-48;
}
void luumatran(int mt[10][10],int k){
char s[10];
int fd,i,j;
printf("nhap file luu ma tran:");
fflush(stdin);
gets(s);
fd=open(s,O_WRONLY);
for(i=1;i<=k;i++){
for(j=1;j<=k;j++)
writeC(mt[i][j],fd);
xuongdong(fd);
}
close(fd);
}
void xuongdong(int fd){
char s[10];
s[0]=10;
int wr= write(fd,s,1);
}
void writeC(int a,int fd){
int k,i,of,wr;
char so[10],s[10];
k=0;
while(a>0){
so[k]=a%10+48;
k=k+1;
a=a/10;
}
for(i=0;i<=k-1;i++)
s[i]=so[k-i-1];
wr=write(fd,s,k);
s[0]=' ';
wr=write(fd,s,1);
if(wr!=-1)printf("
write sucess !
");
else printf("
write error !
");
}
BÀI 39
#include "stdio.h"
#include "sys/types.h"
#include "fcntl.h"
#include "string.h"
#include "sys/file.h"
int convert(char);
main(){
int fd,sg,k=1,sg2=1,d[10][10],j=1,s1,s2,dem=0;
char i[10],s[100];
printf("nhap vao file ma tran:");
fflush(stdin);
gets(s);
printf("
nhap gia tri k ma ban muon tim trong ma tran:%d",&sg);
fd=open(s,O_RDONLY);
while (sg2!=0){
sg2=read(fd,i,1);
if(sg2!=0){
d[k][j]=0;
while(((int)i[0] != 32)&&((int)i[0] != 10))
{
d[k][j]=d[k][j]*10+convert(i[0]);
sg2=read(fd,i,1);
if((int)i[0]==32) j=j+1;
}
if(((int)i[0] == 10)){
k=k+1;
j=1;
}
}
}
k=k-1;
for(s1=1;s1<=k;s1++){
for(s2=1;s2<=k;s2++){
printf("%d ",d[s1][s2]);
if (sg==d[s1][s2]) dem=dem+1;
}
printf("
");
}
if(dem != 0)printf("
gia tri %d xuat hien trong ma tran %d lan !
",sg,dem);
else printf("
gia tri %d khong co trong ma tran!
",sg);
close(fd);
}
int convert(char c){
return (int)c-48;
}
BÀI40
#include "stdio.h"
#include "sys/types.h"
#include "fcntl.h"
#include "string.h"
#include "sys/file.h"
int convert(char),sapxep(int h[100],int l);
main(){
int fd,sg=0,k=0,sg2=1,d[100];
char i[10],s[100];
printf("nhap vao file day so:");
fflush(stdin);
gets(s);
fd=open(s,O_RDONLY);
while (sg2!=0){
sg2=read(fd,i,1);
if(sg2!=0){
if(((int)i[0] != 32)&&((int)i[0] != 10))
k=k+1;
d[k]=0;
while(((int)i[0] != 32)&&((int)i[0] != 10))
{
d[k]=d[k]*10+convert(i[0]);
sg2=read(fd,i,1);
}
}
}
sapxep(d,k);
for(sg=1;sg<=k;sg++) printf("%d ",d[sg]);
close(fd);
}
int convert(char c){
return (int)c-48;
}
int sapxep(int h[100],int l){
int s1,l1,l2,tg;
for(l1=1;l1<=l;l1++)
for(l2=l1;l2<=l;l2++ )
if (h[l1]>=h[l2]){
tg=h[l1];
h[l1]=h[l2];
h[l2]=tg;
}
return 0;
}
BÀI 41
#include "stdio.h"
#include "sys/types.h"
#include "fcntl.h"
#include "string.h"
#include "sys/file.h"
int convert(char);
main(){
int fd,sg=0,k=1,sg2=1,d[10];
char i[10],s[100];
printf("nhap vao file ma tran:");
fflush(stdin);
gets(s);
fd=open(s,O_RDONLY);
while (sg2!=0){
sg2=read(fd,i,1);
if(sg2!=0){
d[k]=0;
while (((int)i[0]!=10)){
if(((int)i[0] != 32))
{
printf("%d ",convert(i[0]));
d[k]=d[k]+convert(i[0]);
}
sg2=read(fd,i,1);
}
printf("tong cac phan tu trong ma tran hang thu %d la : %d
",k,d[k]);
if((int)i[0]==10) k=k+1;
}
}
close(fd);
}
int convert(char c){
return (int)c-48;
}
BÀI 42
#include "stdio.h"
main(){
system("ps -l");
nice(1);
printf("
-----sau khi tang len 1--------------
");
system("ps -l");
nice(2);
printf("
------sau khi tang len 2-------------
");
system("ps -l");
nice(-1);
printf("
________sau khi giam 1_______________
");
system("ps -l");
}
BÀI43
#include "sys/types.h"
#include "stdio.h"
#include "signal.h"
main(){
alarm(3);
}
BÀI 44
#include "sys/types.h"
#include "stdio.h"
#include "signal.h"
main(){
sleep(3);
}
BÀI 45
#include "sys/types.h"
#include "stdio.h"
#include "signal.h"
void SignalAlarm();
int sig=1;
main(){
signal(SIGALRM,SignalAlarm);
alarm(10);
while(sig){
printf("
doi tin hieu ALARM...");
}
}
void SignalAlarm(){
sig=0;
}
BÀI46
#include "stdio.h"
#include "signal.h"
main(){
void (*oldHandler)();
printf("tu day duoc bao ve ngat SIGINT...:");
sleep(5);
oldHandler=signal(SIGINT,SIG_IGN);
printf("
tin hieu ngat dc khoi phuc");
sleep(5);
signal(SIGINT,oldHandler);
printf("
ban co the ngat SIGINT");
sleep(5);
printf("
ok
");
}
BAI47
#include "stdio.h"
#include "sys/types.h"
main(){
int sg,g;
char f[100];
printf("nhap vao ten file can thay doi quyen so huu:");
fflush(stdin);
gets(f);
printf("
nhap vao quyen so huu can thay doi cho file da nhap :");
scanf("%d",&g);
sg=chmod(f,g);
if(sg==-1) printf("
thay doi khong thanh cong!");
else printf("
Thay doi thanh cong !");
}
BÀI48
#include "stdio.h"
#include "sys/types.h"
main(){
int sg,u;
char f[100];
printf("nhap vao ten file can thay doi chu so huu:");
fflush(stdin);
gets(f);
printf("
nhap vao ten chu so huu can thay doi cho file da nhap :");
scanf("%d",&u);
sg=chown(f,u,getgid());
if(sg==-1) printf("
thay doi khong thanh cong!");
else printf("
Thay doi thanh cong !");
}
BÀI49
#include "stdio.h"
#include "sys/types.h"
main(){
int sg,g;
char f[100];
printf("nhap vao ten file can thay doi nhom so huu:");
fflush(stdin);
gets(f);
printf("
nhap vao ten nhom so huu can thay doi cho file da nhap :");
scanf("%d",&g);
sg=chown(f,getuid(),g);
if(sg==-1) printf("
thay doi khong thanh cong!");
else printf("
Thay doi thanh cong !");
}
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