函数指针、函数意外结束问题

[Proteas]

#include<stdio.h>
#include<math.h>
#include<time.h>
#include<stdlib.h>
#include<assert.h>
/*********************************************/
void main()
{
clock_t start,end,over;
int convert(int m);
void process( int size,unsigned char *source,unsigned char *destination,int (*mm)( int));
FILE *file;
int width,height,size;
char *name=NULL;
int a=1;
while(a)
{
printf("Please input your file name: \n");
scanf("%s",name);
if((file=fopen(name,"rb"))=NULL)
printf("Input error!\nEnter 0 to exit.\n");
scanf("%d",&a);
}
a=1;
while(a)
{
printf("Please input the width of your file:\n");
scanf("%d",&width);
if(width<=0)
printf("Input error!\nEnter 0 to exit.\n");
scanf("%d",&a);
}
a=1;
while(a)
{
printf("Please input the height of your file:\n");
scanf("%d",&height);
if(width<=0)
printf("Input error!\nEnter 0 to exit.\n");
scanf("%d",&a);
}
size=(int)(width*height);
unsigned char *source,*destination;
source=(unsigned char *)calloc(size,sizeof(char));
destination=(unsigned char *)calloc(size,sizeof(char));
fread(source,size,1,file);
fclose(file);
start=clock();
end=clock();
over=end-start;
start=clock();
process(size,source,destination, convert);
end=clock();
printf("time: %4.2f s\n",(float)(end-start-over)/CLK_TCK);
fwrite(destination,size,1,file);
fclose(file);
free(source);
free(destination);
}
/*********************************************/
/********************************************/
void process( int size,unsigned char *source,unsigned char *destination, int (*mm)( int ))
{
int i=0,temp;
for(i;i<size;i++)
{
temp=(*mm)(*source(i));//报错：term does not evaluate to a function

if(temp<0)
temp=0;
if(temp>255)
temp=255;
*destination(i)=temp;//报错：term does not evaluate to a function
}
/**************************************************/
/**************************************************/
int convert(int m)
{
int Gray_Level,a=1,back;//报错：local function definitions are illegal
while(a）

{
printf("Please input the Gray_Level of your image:\n");
scanf("%d",&Gray_Level);
if(Gray_Level<=0)
printf("Input error!\nEnter 0 to exit.\n");
scanf("%d",&a);
}
back=Gray_Level-1-m);
return back;
}//报错：unexpected end of file found
编译时提示有四个错误，我在程序中标明了，我不知道错在哪里，该怎么改，谢谢。

[晨星]

void process( int size,unsigned char *source,unsigned char *destination, int (*mm)( int ))
{
int i=0,temp;
for(i;i<size;i++)
{
temp=(*mm)(*source(i));//报错：term does not evaluate to a function

if(temp<0)
temp=0;
if(temp>255)
temp=255;
*destination(i)=temp;//报错：term does not evaluate to a function
}

怎么上面这个函数没有结束的大括号啊？

[snowbirdfly]

恩~~
是不是这个问题阿~~

[Mr_Yang]

temp=(*mm)(*source(i));//报错：term does not evaluate to a function

这个不知道是什么意思。
mm是指向函数得指针，而source是char型的。。。。。。。。

[megaboy]

temp=(*mm)(*source(i));//报错：term does not evaluate to a function
*destination(i)=temp;//报错：term does not evaluate to a function
------------------------------------------------------------------
source和destination都是指针，怎么能当作函数指示符使用呢，应该是：

temp=(*mm)(source[i]);
destination[i]=temp;



int Gray_Level,a=1,back;//报错：local function definitions are illegal
----------------------------------------------------------------------
由于process函数缺了一个大括号}，至使编译器把process函数体延伸到int convert(int m)后面去了，而int convert(int m)是一个函数定义，变成了在process函数体内定义一个函数，但C是不支持函数嵌套的，因此会说函数定义非法。后面的unexpected end of file found报错也是这个原因，把大括号}加回去应该就不会了。

[Proteas]

我加了半个括号后，前两个错误还在。
void process( int size,unsigned char *source,unsigned char *destination, int (*mm)( int ))
{
int i=0,temp;
for(i;i<size;i++)
{
temp=(*mm)(*source(i));//报错：term does not evaluate to a function

if(temp<0)
temp=0;
if(temp>255)
temp=255;
*destination(i)=temp;//报错：term does not evaluate to a function
}
}

怎么上面这个函数没有结束的大括号啊？

[wanguodu]

LZ错误实在太多，就不一一指出了，下面是修改了一些明显错误后的程序，LZ有不懂的再问吧：

#include<stdio.h>
#include<math.h>
#include<time.h>
#include<stdlib.h>
#include<string.h>
#include<assert.h>
/*********************************************/
void main()
{
clock_t start,end,over;
int convert(int m);
void process( int size,unsigned char *source,unsigned char *destination,int (*mm)( int));
FILE *file;
int width,height,size;
char name[80];//char *name=NULL;
int a=1;

memset(name, 0, sizeof(name));

while(a != 0)
{
a = 0;

printf("Please input your file name: ");
scanf("%s", name);
if((file=fopen(name,"r+b"/* 错，应以读和写方式打开， "rb"*/))/*错，=*/==NULL)
{
printf("Cannot open file %s\n", name);
printf("Type 0 to exit the program, other value to try again\n");

fflush(stdin);
scanf("%d", &a);
if(a == 0)
{
exit(-1);
}
}
}
a=1;
while(a)
{
a = 0;

printf("Please input the width of your file:\n");
scanf("%d", &width);
if(width <= 0)
{
printf("width input illegal\n");
printf("Type 0 to exit the program, other value to try again\n");
fflush(stdin);
scanf("%d",&a);
if(a == 0)
{
exit(-1);
}
}
}
a=1;
while(a)
{
a = 0;
printf("Please input the height of your file:\n");
scanf("%d",&height);
if(height<=0)
{
printf("height input illegal\n");
printf("Type 0 to exit the program, other value to try again\n");
fflush(stdin);
scanf("%d",&a);
if(a == 0)
{
exit(-1);
}
}
}
size=(int)(width*height);
unsigned char *source,*destination;
source=(unsigned char *)calloc(size,sizeof(char));
destination=(unsigned char *)calloc(size,sizeof(char));
fread(source,size,1,file);
//错，后面还要写文件呢，fclose(file);
start=clock();
end=clock();
over=end-start;
start=clock();
process(size,source,destination, convert);
end=clock();
printf("time: %4.2f s\n",(float)(end-start-over)/CLK_TCK);
fwrite(destination,size,1,file);
fclose(file);
free(source);
free(destination);
}
/*********************************************/
/********************************************/
void process( int size,unsigned char *source,unsigned char *destination, int (*mm)( int ))
{
int i=0,temp;
for(i;i<size;i++)
{
temp=(*mm)(source[i]);//报错：term does not evaluate to a function

if(temp<0)
temp=0;
if(temp>255)
temp=255;
destination[i]=temp;//报错：term does not evaluate to a function
}
}
/**************************************************/
/**************************************************/
int convert(int m)
{
int Gray_Level,a=1,back;//报错：local function definitions are illegal
while(a)
{
a = 0;
printf("Please input the Gray_Level of your image:\n");
scanf("%d",&Gray_Level);
if(Gray_Level<=0)
{
printf("Input error!\nEnter 0 to exit.\n");
fflush(stdin);
scanf("%d",&a);
if(a == 0)
{
exit(-1);
}
}
}
back=Gray_Level-1-m;
return back;
}//报错：unexpected end of file found

[Proteas]

temp=(*mm)(source[i]);//
temp=(*mm)(*source(i));//
source 已经指向了数组首地址，这两个有什么不同？

[megaboy]

source(i)表示调用函数，source[i]是数组引用。

[wanguodu]

fflush(stdin); //清除标准输入中的残留字符，以便后面的scanf能得到正确输入
exit(-1); //出现了无法继续的情况，如文件打不开，并且用户也同意了，因此退出程序
memset(name, 0, sizeof(name));
－－－－－－－－－－－－－－－－－
清零是为了后面的：printf("Cannot open file %s\n", name); 因为可能出现用户直接输入回车的情况，不清零的话，这句会打印乱码

temp=(*mm)(source[i])这个 megaboy已经说过了。

[Proteas]

unsigned char *source,*destination;
source=(unsigned char *)calloc(size,sizeof(char));
destination=(unsigned char *)calloc(size,sizeof(char));
//这里定义了两个指针
void process( int size,unsigned char *source,unsigned char *destination, int (*mm)( int ))
{
int i=0,temp;
for(i;i<size;i++)
{
temp=(*mm)(source[i]);//报错：term does not evaluate to a function

if(temp<0)
temp=0;
if(temp>255)
temp=255;
destination[i]=temp;//报错：term does not evaluate to a function
}
}int convert(int m)
{
int Gray_Level,a=1,back;//报错：local function definitions are illegal
while(a)
{
a = 0;
printf("Please input the Gray_Level of your image:\n");
scanf("%d",&Gray_Level);
if(Gray_Level<=0)
{
printf("Input error!\nEnter 0 to exit.\n");
fflush(stdin);
scanf("%d",&a);
if(a == 0)
{
exit(-1);
}
}
}
back=Gray_Level-1-m;
return back;
}//
/******************************************/
还是不明白，
temp=(*mm)(source[i]);//
temp=(*mm)(*source(i));//
source 已经指向了数组首地址，这两个有什么不同？
(*mm)(int)的参数是一个数据，上面的参数都是同一个数据，一个用指针一个用数组而已，谢谢。

[Proteas]

感觉自己的基础还是太差，我想看些c语言比较高级用法的基础书，可以推荐基本吗？电子书也行，[e-mail]

[megaboy]

source是unsigned char类型的，而mm的形参是int的，要转换过来：

temp=(*mm)((int)source[i]);

[Proteas]

谢谢大家。

[Proteas]

fflush(stdin);
exit(-1);
memset(name, 0, sizeof(name));
temp=(*mm)(source[i])
这些地方不懂。