foo.c: In function 'main':
foo.c:6:48: warning: unused variable 'sum' [-Wunused-variable]
    6 |  int m,n,p,i,j,a[100][100]={0},b[100][100]={0},sum=0,c[100][100]={0},k;
      |                                                ^~~
foo.c:7:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    7 |  scanf("%d%d%d",&m,&n,&p);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~
foo.c:11:4: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   11 |    scanf("%d",&a[i][j]);
      |    ^~~~~~~~~~~~~~~~~~~~
foo.c:16:4: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   16 |    scanf("%d",&b[i][j]);
      |    ^~~~~~~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务