C和指针课后习题

#include <assert.h>#include <stdio.h>#define NULL 0 #define NUL '\0'#define TRUE 1#define FALSE 0char *match( char *str, char *want ){while( *want != NUL )if( *str++ != *want++ )return NULL;return str;}int del_substr( char *str, char  *substr ){char *next;while( *str != NUL ){next = match( str, substr );if( next != NULL )break;str++;}if( *str == NUL )return FALSE;while( *str++ = *next++ );return TRUE;}int main(){int del_substr( char *str, char  *substr );char *match( char *str, char *want );char src[20] = "ABCDEF";char str[] = "CD";int number=0;number =del_substr(src,str);if (number==NULL){printf("Not find!");}else{printf("%s",src);}return 0;}

刚开始看指针，觉得很迷糊，match函数已经改变了str的指针值，怎么在del函数中，没有改变。想了一下，应该会是形参和实参的概念不清楚吧。