#include <stdio.h>
main()
{
    int N,i,sum;
    int y[N][2];
    scanf("%d",&N);
    for(i=0;i<N;i++)
    {
        scanf("%d %d",&y[i][0],&y[i][1]);
    }
    printf("\n");
    for(i=0;i<N;i++)
    {
        sum=y[i][0]+y[i][1];
        printf("%d",sum);
    }
    printf("\n");
    return 0;
}

C:\Users\sony\Desktop\1.c(5) : error C2057: expected constant expression
C:\Users\sony\Desktop\1.c(5) : error C2466: cannot allocate an array of constant size 0
C:\Users\sony\Desktop\1.c(5) : error C2133: 'y' : unknown size
执行 cl.exe 时出错.

  为什么不允许        那该怎么改

好像还是不行

不行的  更多错了
:\Users\sony\Desktop\1.c(7) : error C2143: syntax error : missing ';' before 'type'
C:\Users\sony\Desktop\1.c(12) : error C2065: 'y' : undeclared identifier
C:\Users\sony\Desktop\1.c(12) : error C2109: subscript requires array or pointer type
C:\Users\sony\Desktop\1.c(12) : error C2109: subscript requires array or pointer type
C:\Users\sony\Desktop\1.c(12) : error C2102: '&' requires l-value
C:\Users\sony\Desktop\1.c(12) : error C2109: subscript requires array or pointer type
C:\Users\sony\Desktop\1.c(12) : error C2109: subscript requires array or pointer type
C:\Users\sony\Desktop\1.c(12) : error C2102: '&' requires l-value
C:\Users\sony\Desktop\1.c(17) : error C2109: subscript requires array or pointer type
C:\Users\sony\Desktop\1.c(17) : error C2109: subscript requires array or pointer type
C:\Users\sony\Desktop\1.c(17) : error C2109: subscript requires array or pointer type
C:\Users\sony\Desktop\1.c(17) : error C2109: subscript requires array or pointer type
C:\Users\sony\Desktop\1.c(21) : warning C4013: 'system' undefined; assuming extern returning int
执行 cl.exe 时出错.

1.obj - 1 error(s), 0 warning(s)

怎么动态申请内存

不行的  更多错了
:\Users\sony\Desktop\1.c(7) : error C2143: syntax error : missing ';' before 'type'
 C:\Users\sony\Desktop\1.c(12) : error C2065: 'y' : undeclared identifier
 C:\Users\sony\Desktop\1.c(12) : error C2109: subscript requires array or pointer type
 C:\Users\sony\Desktop\1.c(12) : error C2109: subscript requires array or pointer type
 C:\Users\sony\Desktop\1.c(12) : error C2102: '&' requires l-value
 C:\Users\sony\Desktop\1.c(12) : error C2109: subscript requires array or pointer type
 C:\Users\sony\Desktop\1.c(12) : error C2109: subscript requires array or pointer type
 C:\Users\sony\Desktop\1.c(12) : error C2102: '&' requires l-value
 C:\Users\sony\Desktop\1.c(17) : error C2109: subscript requires array or pointer type
 C:\Users\sony\Desktop\1.c(17) : error C2109: subscript requires array or pointer type
 C:\Users\sony\Desktop\1.c(17) : error C2109: subscript requires array or pointer type
 C:\Users\sony\Desktop\1.c(17) : error C2109: subscript requires array or pointer type
 C:\Users\sony\Desktop\1.c(21) : warning C4013: 'system' undefined; assuming extern returning int
执行 cl.exe 时出错.

1.obj - 1 error(s), 0 warning(s)

好的