判断是否为素数

include <stdio.h>

int main ()
{
int n=1;
int x;
scanf("%d",&x);
int biaozhi=1;
for (n=2;n<x;n++){
if(x%n0 ){
biaozhi=0;此处可加break;}
}
if (biaozhi0)printf("NO");
else printf("yes");
return 0;
}
判断100内素数

include <stdio.h>

int main ()
{

int x;

for (x=2;x<100;x++){
int n=1;
int biaozhi=1;
for (n=2;n<x;n++){
	if(x%n==0 ){
	biaozhi=0;break;}
}
if (biaozhi==1) printf(" %d",x);}

return 0;
}
输出前50个素数

include <stdio.h>

int main ()
{

int x=2;
int cnt=0;
while (cnt<50){
int n=1;
int biaozhi=1;
for (n=2;n<x;n++){
	if(x%n==0 ){
	biaozhi=0;break;}
}
if (biaozhi==1) {
printf(" %d",x);cnt++;}x++;}

return 0;
}