foo.c:2:6: warning: return type of 'main' is not 'int' [-Wmain]
    2 | void main()
      |      ^~~~
foo.c: In function 'main':
foo.c:4:5: error: expected ',' or ';' before 'scanf'
    4 |     scanf("%d",&n);          //输入该二进制数
      |     ^~~~~
foo.c:5:5: error: 'while\U0000ff08n\U0000ff09' undeclared (first use in this function)
    5 |     while（n）               //循环条件为n，即二进制数n在不为0的时候程序一直成立
      |     ^~~~~~~~~~
foo.c:5:5: note: each undeclared identifier is reported only once for each function it appears in
foo.c:5:15: error: expected ';' before '{' token
    5 |     while（n）               //循环条件为n，即二进制数n在不为0的时候程序一直成立
      |               ^
      |               ;
    6 |      { sum+=(n%10)*p;       //数字中所有位乘以本位的位权再加和
      |      ~         
foo.c:3:17: warning: unused variable 'p' [-Wunused-variable]
    3 | {   int n,sum=0,p=1          //n为二进制数，sum为每一位计算所加的和，p为位权
      |                 ^
foo.c:3:11: warning: unused variable 'sum' [-Wunused-variable]
    3 | {   int n,sum=0,p=1          //n为二进制数，sum为每一位计算所加的和，p为位权
      |           ^~~
foo.c:3:9: warning: unused variable 'n' [-Wunused-variable]
    3 | {   int n,sum=0,p=1          //n为二进制数，sum为每一位计算所加的和，p为位权
      |         ^

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