foo.c: In function 'main':
foo.c:5:1: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
 scanf ("%d%d",&n,&m);
 ^~~~~~~~~~~~~~~~~~~~
foo.c:6:24: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
 for (int i=1;i<=n;i++){scanf("%d",&num[i]);}
                        ^~~~~~~~~~~~~~~~~~~
foo.c:9:1: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d",&opt);
 ^~~~~~~~~~~~~~~~
foo.c:10:12: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
 if(opt==1){scanf("%d%d%d",&l,&r,&v);
            ^~~~~~~~~~~~~~~~~~~~~~~~
foo.c:14:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d",&l,&r);
     ^~~~~~~~~~~~~~~~~~~~

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