第八章：指针06

让编程改变世界

Change the world by program

字符指针作函数参数

出错了：关于a[]和*a的一些区别！ [codesyntax lang="c"]

#include <stdio.h>void  main()
{void copy_string( char *from, char *to );char *a = "I am a teacher.";char b[] = "You are a student."; //此处应该定义为char b[] = "You are a student.";//区别两者反汇编代码并解释其意义//谈谈五个区!printf("String a = %snString b = %sn", a, b);printf("copy string a to string b:n");copy_string(a, b);printf("nString a = %snString b = %sn", a, b);
}void  copy_string( char *from, char *to )
{for( ; *from != '�'; from++,to++){*to = *from;}*to = '�';
}

[/codesyntax]

优化：对 copy_string 函数还可作简化

方法一

[codesyntax lang="c"]

#include <stdio.h>void  main()
{void copy_string( char *from, char *to );char *a = "I am a teacher.";char b[] = "You are a student.";printf("String a = %snString b = %sn", a, b);printf("copy string a to string b:n");copy_string(a, b);printf("nString a = %snString b = %sn", a, b);
}void  copy_string( char *from, char *to )
{while( (*to = *from) != '�' ){to++;from++;}
}

[/codesyntax]

方法二

[codesyntax lang="c"]

#include <stdio.h>void  main()
{void copy_string( char *from, char *to );char *a = "I am a teacher.";char b[] = "You are a student.";printf("String a = %snString b = %sn", a, b);printf("copy string a to string b:n");copy_string(a, b);printf("nString a = %snString b = %sn", a, b);
}void  copy_string( char *from, char *to )
{while( (*to++ = *from++) != '�'){;}
}

[/codesyntax]

方法三

[codesyntax lang="c"]

#include <stdio.h>void  main()
{void copy_string( char *from, char *to );char *a = "I am a teacher.";char b[] = "You are a student.";printf("String a = %snString b = %sn", a, b);printf("copy string a to string b:n");copy_string(a, b);printf("nString a = %snString b = %sn", a, b);
}void  copy_string( char *from, char *to )
{while( *from != '�' ){*to++ = *from++;}*to = '�';
}

[/codesyntax]

方法四

[codesyntax lang="c"]

#include <stdio.h>void  main()
{void copy_string( char *from, char *to );char *a = "I am a teacher.";char b[] = "You are a student.";printf("String a = %snString b = %sn", a, b);printf("copy string a to string b:n");copy_string(a, b);printf("nString a = %snString b = %sn", a, b);
}void  copy_string( char *from, char *to )
{while( *to++ = *from++ ){;    // '�' == 0}
}

[/codesyntax]

方法五

[codesyntax lang="c"]

#include <stdio.h>void  main()
{void copy_string( char *from, char *to );char *a = "I am a teacher.";char b[] = "You are a student.";printf("String a = %snString b = %sn", a, b);printf("copy string a to string b:n");copy_string(a, b);printf("nString a = %snString b = %sn", a, b);
}void  copy_string( char *from, char *to )
{for( ; *to++ = *from++; ){;}
}

[/codesyntax]

方法六

[codesyntax lang="c"]

#include <stdio.h>void  main()
{void copy_string( char *from, char *to );char *a = "I am a teacher.";char b[] = "You are a student.";printf("String a = %snString b = %sn", a, b);printf("copy string a to string b:n");copy_string(a, b);printf("nString a = %snString b = %sn", a, b);
}void  copy_string( char from[], char to[] )
{char *p1, *p2;p1 = from;p2 = to;while( (*p2++ = *p1++) != '�' ){;}
}

[/codesyntax] [buy] 获得所有教学视频、课件、源代码等资源打包 [/buy] [Downlink href='http://kuai.xunlei.com/d/LHAPZBNXYNES']视频下载[/Downlink]