3.指针与字符串.ppt.ppt

fun1(int x,int y ,int *cp,int *dp){*cp=x+y; *dp=x-y;}fun2(int *a,int b){int c,c=*a;*a=b;b=c;}void main(){int a,b,c,d;a=30;b=50;fun1(a,b,&c,&d);fun2(&c,d); printf(“%d,%d\n”,c,d);}请写出输出结果:?指针与字符串–字符串表示形式?用字符数组实现例main( ) { char string[]=“I love China!”; printf(“%s\n”,string); printf(“%s\n”,string+7); }IloveChistring[0]string[1]string[2]string[3]string[4]string[5]string[6]string[7]string[8]string[9]stringstring[10]string[11]string[12]string[13]n!a\0用字符指针实现例main( ) { char *string=“I love China!”; printf(“%s\n”,string);string+=7; while(*string) { putchar(string[0]); string++; } }IloveChistringn!a\0字符指针初始化:把字符串首地址赋给string? char *string; string=“I love China!”;string*string!=0–\.\0Iaaeceh\.\0mtavoid copy_string(char to[],char from[]){ int i=0; while(from[i]!='\0') { to[i]=from[i];i++; } to[i]='\0';}main(){ char str_t[80], str_s[80];gets(str_s);copy_string(str_t,str_s); printf("\n str_t=%s\n str_s=%s\n", str_t,str_s);}void copy_string(char *p1,char *p2){ for(;*p2!='\0';p1++,p2++)*p1=*p2;*p1='\0';}main(){ char str_t[80], str_s[80]; gets(str_s);copy_string(str_t,str_s); printf("\n str_t=%s\n str_s=%s\n", str_t,str_s);}例用函数调用实现字符串连接用字符指针变量作参数void linkstr(char *p1,char *p2){while(*p1)p1++; while (*p2){*p1=*p2;p1++;p2++;}*p1='\0';return ;}main(){char str_t[80],str_s[80];gets(str_t); gets(str_s);linkstr(str_t,str_s);printf("%s\n%s\n",str_s,str_t);}}–字符指针变量与字符数组char *cp; 与char str[20];?str由若干元素组成,每个元素放一个字符;而cp中存放字符串首地址?char str[20]; str=“I love China!”; (?) char *cp; cp=“I love China!”; (?)?str是地址常量;cp是地址变量?cp接受键入字符串时,必须先开辟存储空间例char str[10]; scanf(“%s”,str); (?)而char *cp; scanf(“%s”, cp); (?)改为: char *cp,str[10]; cp=str; scanf(“%s”,cp); (?)char str[]={“He