#include <bits/stdc++.h>
using namespace std;
int main()
{
	int ans=0;
	char ch[6];
	gets(ch);
	for(int i=0;i<strlen(ch);i++)
	{
		if(ch[i]==' ') ans++;
	}
	printf("%d",strlen(ch)-ans);
	return 0;
}

之后出现了

/tmp/compiler_wxzpu2qd/src: 在函数‘int main()’中:
/tmp/compiler_wxzpu2qd/src:7:2: 错误：‘gets’ was not declared in this scope; did you mean ‘fgets’?
    7 |  gets(ch);
      |  ^~~~
      |  fgets
/tmp/compiler_wxzpu2qd/src:8:15: 警告：comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Wsign-compare]
    8 |  for(int i=0;i<strlen(ch);i++)
      |              ~^~~~~~~~~~~
/tmp/compiler_wxzpu2qd/src:12:11: 警告：格式 ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘size_t’ {aka ‘long unsigned int’} [-Wformat=]
   12 |  printf("%d",strlen(ch)-ans);
      |          ~^  ~~~~~~~~~~~~~~
      |           |            |
      |           int          size_t {aka long unsigned int}
      |          %ld

这样的东西该怎么办