1.字符串数组,字符串指针可以直接输出
char s2[30]="I am a student"; cout<<s2<<endl; char *p="I am a student"; cout<<p<<endl; cout<<p[2]<<endl;
2.指针变量p分配4个存储单元。
用指针变量处理字符串,要比用数组处理字符串方便。
指针变量用于存放变量地址,而地址通常为4字节,所以指针变量的长度均为4个字节。
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#include<stdio.h> void main() { int c=sizeof(char);//1 int i=sizeof(int);//4 int l=sizeof(long);//4 int d=sizeof(double);//8 int p=sizeof(int *);//4 int q=sizeof(char *);//4 printf("%d %d ",c,i); printf("%d %d ",l,d); printf("%d %d ",p,q); }
3.static关键字定义静态变量时,相当于只执行第一次。下面程序结果为6
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#include<stdio.h> #include<stdlib.h> c(int i) { static int c=0; c+=i; printf("%d ",c); return c; } int main() { int j,i; for(i=0;i<=3;i++) { j=c(i); } printf("%d ",j); }
4.printf()函数从右往左执行
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int *p; int a[]={3,12,9}; p=&a; printf("%d %d",*p,*p++);//12 3
5.循环次数不确定时如何设计?
for (;*p2++=*p1++;); //用指针拷贝字符串
【例7.10】用指针实现字符串拷贝。执行后输出:
s1= I am a student
s2= I am a student
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#include<iostream> #include<string.h> using namespace std; int main(void) { char *p1="I am a student"; char s1[30],s2[30]; strcpy(s1,p1); //用命令拷贝字符串 char *p2=s2; //将数组s2首地址赋p2 for (;*p2++=*p1++;); //用指针拷贝字符串 cout<<"s1="<<s1<<endl; cout<<"s2="<<s2; }
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#include<iostream> #include<string.h> using namespace std; int main(void) { char *p1="I am a student";//14 char s1[30],s2[30]; strcpy(s1,p1); //用命令拷贝字符串 char *p2=s2; //将数组s2首地址赋p2 int i=1; for (;*p1++;i++)cout<<i<<endl; //用指针拷贝字符串 cout<<"s1="<<s1<<endl; }
while(*p1!=' '){...}
6.strlen()求字符串长度
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#include<stdio.h> #include<string.h>//包含该头文件 int main() { char *p="abcbc"; int a=strlen(p); printf("%d",a);//5 }
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to be continued…