#include<stdio.h>
#define N 3
void main()
{
     int a[N][N] = { {7,-5,3},{2,8,-6},{1,-4,-2}};
     int b[N][N] = { {3,6,-9},{2,-8,3},{5,-2,-7}};
     int c[N][N]:            
     int i,j;
     for(i=0;i<N;i++)
         for(j=0;j<N;j++)
             c[i][j] =a[i][j] +b[i][j];
         for(i=0;i<N;i++){
             for(j=0,j<N,j++)
                 printf("%5d",c[i][j]);
             printf("\n");
         }
}
报错:
D:\c语言练习上机练习\第20章\第20章\aaa\aaa11.cpp(7) : error C2601: 'c' : local function definitions are illegal
D:\c语言练习上机练习\第20章\第20章\aaa\aaa11.cpp(7) : error C2063: 'c' : not a function
D:\c语言练习上机练习\第20章\第20章\aaa\aaa11.cpp(8) : error C2969: syntax error : ',' : expected member function definition to end with '}'
D:\c语言练习上机练习\第20章\第20章\aaa\aaa11.cpp(8) : error C2065: 'j' : undeclared identifier
D:\c语言练习上机练习\第20章\第20章\aaa\aaa11.cpp(9) : error C2065: 'i' : undeclared identifier
D:\c语言练习上机练习\第20章\第20章\aaa\aaa11.cpp(13) : error C2143: syntax error : missing ';' before ')'
D:\c语言练习上机练习\第20章\第20章\aaa\aaa11.cpp(13) : error C2143: syntax error : missing ';' before ')'
执行 cl.exe 时出错.
请高手看看哪里错了

“int c[N][N]: ”应该是分号

多看提示错误代码。

我把你的程序在VC++6.0上运行了一下，发现了两个错误，呵呵。。。
// aslkd.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include<stdio.h>
#define N 3

int main(int argc, char* argv[])
{
   
     int a[N][N] = { {7,-5,3},{2,8,-6},{1,-4,-2}};
     int b[N][N] = { {3,6,-9},{2,-8,3},{5,-2,-7}};
     int c[N][N]； //这里应该是分号；           
     int i,j;
     for(i=0;i<N;i++)
         for(j=0;j<N;j++)
             c[i][j] =a[i][j] +b[i][j];
         for(i=0;i<N;i++)
         {
             for(j=0;j<N;j++)//这里也应该是分号；
                 printf("%5d",c[i][j]);
             printf("\n");
         }
    printf("Hello World!\n");
    return 0;
}

#include<stdio.h>
#define N 3
void main()
{
     int a[N][N] = { {7,-5,3},{2,8,-6},{1,-4,-2}};
     int b[N][N] = { {3,6,-9},{2,-8,3},{5,-2,-7}};
     int c[N][N];            
     int i,j;
     for(i=0;i<N;i++)
         for(j=0;j<N;j++)
             c[i][j] =a[i][j] +b[i][j];
         for(i=0;i<N;i++)
         {
             for(j=0;j<N;j++)
                 printf("%5d",c[i][j]);
             printf("\n");
         }
}