NO.194 指针指向
Q:若有double *p,x;int i=5;使指针变量p指向元素x的语句是
A.p=&x;
B.p=x;
C.p=x;
D.p=&(x+i);
B×p=x是指向数组首元素地址
A.
#include <stdio.h>
#include <math.h>
int main()
{
double *p,x;int i=5;
p=&x;
printf("p=%lf\n",p);//p=0.000000
printf("*p=%lf\n",*p);//*p=0.000000
printf("x=%lf\n",x);//x=0.000000
return 0;
}
B.
#include <stdio.h>
#include <math.h>
int main()
{
double *p,x;int i=5;
p=x;
printf("p=%lf\n",p);//p=0.000000
printf("*p=%lf\n",*p);//*p=0.000000
printf("x=%lf\n",x);//x=0.000000
return 0;
}
C.
#include <stdio.h>
#include <math.h>
int main()
{
double *p,x;int i=5;
p=x;
printf("p=%lf\n",p);
printf("*p=%lf\n",*p);
printf("x=%lf\n",x);
return 0;
}
7 11
cannot convert 'double' to 'double*' in assignment
D.
#include <stdio.h>
#include <math.h>
int main()
{
double *p,x;int i=5;
p=&(x+i);
printf("p=%lf\n",p);
printf("*p=%lf\n",*p);
printf("x=%lf\n",x);
return 0;
}
7 14
lvalue required as unary '&' operand
[错误]左值需要作为一元'&'操作数
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