typedef简化

/***
mystrcat:
***/
#include<stdio.h>
#include<string.h>

char *mystrcat(char *s1,char *s2)
{
    strcat(s1,s2);
    return s1;
}

int main()
{
    char s1[] = "hello";
    char s2[] = " world";
    char *s = mystrcat(s1,s2);
    printf("s = %s\n",s);
    return ;
}

指向函数的指针：

#include<stdio.h>
#include<string.h>

char *mystrcat(char *s1,char *s2)
{
    strcat(s1,s2);
    return s1;
}

char *test(char *(*p)(char *,char *),char *s1,char *s2)
{
    return p(s1,s2);
}

int main()
{
    char s1[] = "hello";
    char s2[] = " world";
    //char *s = mystrcat(s1,s2);
    char *s = test(mystrcat,s1,s2);
    printf("s = %s\n",s);
    return ;
}

typedef简化：

#include<stdio.h>
#include<string.h>

char *mystrcat(char *s1,char *s2)
{
    strcat(s1,s2);
    return s1;
}

typedef char*(*STRCAT)(char *,char *);

char *test(STRCAT p,char *s1,char *s2)
{
    return p(s1,s2);
}

int main()
{
    char s1[] = "hello";
    char s2[] = " world";
    //char *s = mystrcat(s1,s2);
    char *s = test(mystrcat,s1,s2);
    printf("s = %s\n",s);
    return ;
}