#include <stdio.h>
int main()
{
    int n, a, i;
    char s[10001],t[2];
    scanf("%d", &n);
    scanf("%s", s);
    scanf("%s", t);
    a = -1;
    for(i = 0; i < n; i++)
        if(s[i] == t[0]) {
            a = i;
            break;
        }
 
    printf("%d\n", a);
 
    return 0;
}

#include<iostream> using namespace std; const int maxn=1001; char a[maxn]; int main(){ int n; cin>>n; for(int i=0;i<n;i++){ cin>>a[i]; } char b; int c=-1; cin>>b; for(int i=0;i<n;i++){ if(b==a[i]){ c=i; break; } } cout<<c; return 0; }

#include <iostream>
#include <string>
using namespace std;
int main(){
	ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	string s;
	int n;
	char c;
	cin >> n;
	cin >> s;
	cin >> c;
	int ans = -1;
	for(int i = 0 ; i < n ; i++){
		if(s[i] == c){
			ans = i;
			break;
		}
	}
	cout << ans;
	return 0;
}

#include<iostream> using namespace std;

int main() { int n,i; cin>>n; char a[n],b; for(i=0;i<n;i++) { cin>>a[i]; } cin>>b; for(i=0;i<n;i++) { if(a[i]==b) { cout<<i<<endl; break; } } if(a[i]!=b) cout<<"-1"<<endl; return 0; }

#include <stdio.h>
int main(){
    int n,a=-1;
    char str[10001];
    scanf("%d",&n);
    scanf("%s",str);
    char target;
    scanf(" %c",&target);
    for(int i=0;i<n;i++){
        if(str[i]==target){
            a=i;
            break;
        }
    } 
    printf("%d\n",a);
    return 0;
}

#include<stdio.h>
#include<stdlib.h>
int main()
{
    int j=-1;
  int n; scanf("%d",&n); 
  char *str=(char*)malloc((n+1)*sizeof(char)); 
  scanf("%s",str);
  char position; scanf(" %c",&position);
  for(int i=0;i<n;i++){
    if(str[i]==position){j=i; break;}
  }
  printf("%d",j);
  free(str);
    return 0;
}
简单易懂

#include <stdio.h>
int main()
{
    int n,i=1,null;
    scanf("%d",&n);
    null=getchar();
    int a[n],b;
    while(i<=n){a[i]=getchar();i++;}
    null=getchar();
    b=getchar();
    //i=1;
    //while(i<=n){printf("%d,%d\n",&a[i],b);i++;}
    i=n;
    int c=-1;
    
    while (i>=1)
    {
        if (a[i]==b)
        {
            c=i-1;
        }
        i--;
    }
    
    printf("%d",c);
    
    return 0;
}//

#include <stdio.h> #include <string.h>

int find_first_position(char str[], int n, char target) { for (int i = 0; i < n; i++) { if (str[i] == target) { return i; } } return -1; }

int main() { int n; scanf("%d", &n);

char str[10001]; scanf("%s", str);

char target; scanf(" %c", &target);

int position = find_first_position(str, n, target); printf("%d\n", position);

return 0;

}

#include<iostream> using namespace std; int main() {//迭代i，n 模型是数组找(for循环)角标a[n]，再判断因此变量加一（b），所以i n a b四变量 int i,n;cin>>n; char a[n],b; for(i=0;i<n;i++) {cin>>a[i];} cin>>b; for(i=0;i<n;i++) { if (a[i]==b) {cout<<i<<endl;break;}}

if(a[i]!=b)
cout<<"-1"<<endl;

return 0;

}

#include<stdio.h> int main(){ int n,t=-1; char s[10001],b[100]; scanf("%d",&n); scanf("%s",s); scanf("%s",b); for( int i=0;i<n;i++) if(s[i]==b[0]) {t=i; break;}

printf("%d",t);
return 0;}

#include <iostream>
#include <string.h>
#include <stdio.h>
#include <algorithm>
using namespace std;
int main(){ 
	int n,sum=-1;
	string s;
	cin>>n>>s;
	char a;
	cin>>a; 
	for(int j=0;j<n;j++)
	{
		if(a == s[j])
		{
		sum=j;break;
		}			 
	}
	cout<<sum;
	return 0;
}