diff --git a/code_study/Baekjoon/c/10809.c b/code_study/Baekjoon/c/10809.c
new file mode 100644
index 0000000..72ccb1b
--- /dev/null
+++ b/code_study/Baekjoon/c/10809.c
@@ -0,0 +1,18 @@
+#include <stdio.h>
+int main(){
+    int arr[26] = {-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1};
+    int temp=0;
+    char s[101];
+    scanf("%s",s);
+    for(int i=0; s[i]!='\0'; i++){
+        temp = (int)(s[i]-'a');
+        if(arr[temp]==-1) arr[temp]=i;
+    }
+
+    for(int i=0; i<26; i++){
+        printf("%d ",arr[i]);
+    }
+
+    return 0;
+
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/1152.c b/code_study/Baekjoon/c/1152.c
new file mode 100644
index 0000000..ea25c11
--- /dev/null
+++ b/code_study/Baekjoon/c/1152.c
@@ -0,0 +1,19 @@
+#include <stdio.h>
+
+int main(){
+    char s[1000001];
+    scanf("%[^\n]",s);
+
+    int n=0;
+
+    if(s[0]!=' ') n=1;
+
+    for(int i=0; s[i+1]!='\0'; i++){
+        if((s[i]==' ') && (s[i+1]!=' ')) n++;
+    }
+
+    printf("%d",n);
+
+    return 0;
+
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/11654.c b/code_study/Baekjoon/c/11654.c
new file mode 100644
index 0000000..db8fa4a
--- /dev/null
+++ b/code_study/Baekjoon/c/11654.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+int main(){
+    char c;
+    c = getchar();
+    printf("%d",c);
+    return 0;
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/11718.c b/code_study/Baekjoon/c/11718.c
new file mode 100644
index 0000000..a92b979
--- /dev/null
+++ b/code_study/Baekjoon/c/11718.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+int main(){
+    char s;
+    while(scanf("%c",&s)!= EOF){
+        printf("%c",s);
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/11720.c b/code_study/Baekjoon/c/11720.c
new file mode 100644
index 0000000..ceac60b
--- /dev/null
+++ b/code_study/Baekjoon/c/11720.c
@@ -0,0 +1,12 @@
+#include <stdio.h>
+int main(){
+    int n, sum=0;
+    char s[101];
+    scanf("%d",&n);
+    scanf("%s",s);
+    for(int i=0; i<n; i++){
+        sum += (int)(s[i]-'0');
+    }
+    printf("%d",sum);
+    return 0;
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/2675.c b/code_study/Baekjoon/c/2675.c
new file mode 100644
index 0000000..0fb3b0c
--- /dev/null
+++ b/code_study/Baekjoon/c/2675.c
@@ -0,0 +1,23 @@
+#include <stdio.h>
+
+int main(){
+    int t,n;
+    char s[20];
+
+    scanf("%d",&t);
+
+    for(int i=0; i<t; i++){
+        
+        scanf("%d %s",&n,s);
+
+        for(int j=0; s[j]!='\0'; j++){
+            for(int k=0; k<n; k++){
+                printf("%c",s[j]);
+            }
+        }
+
+        printf("\n");
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/2743.c b/code_study/Baekjoon/c/2743.c
new file mode 100644
index 0000000..7d5f289
--- /dev/null
+++ b/code_study/Baekjoon/c/2743.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+int main(){
+    char s[101];
+    int l=0;
+    gets(s);
+    for(l=0; s[l]!='\0'; l++);
+    printf("%d",l);
+    return 0;
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/27866.c b/code_study/Baekjoon/c/27866.c
new file mode 100644
index 0000000..d511304
--- /dev/null
+++ b/code_study/Baekjoon/c/27866.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+int main(){
+    char s[1001];
+    int i;
+    scanf("%s",s);
+    scanf("%d",&i);
+    printf("%c",s[i-1]);
+    return 0;
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/2908.c b/code_study/Baekjoon/c/2908.c
new file mode 100644
index 0000000..6748d45
--- /dev/null
+++ b/code_study/Baekjoon/c/2908.c
@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <stdlib.h>
+/*atoi*/
+int main(){
+    char a[4], b[4];
+    char temp;
+    int x,y;
+
+    scanf("%s %s",a,b);
+
+    temp = a[0];
+    a[0] = a[2];
+    a[2] = temp;
+
+    temp = b[0];
+    b[0] = b[2];
+    b[2] = temp;
+
+    x = atoi(a);
+    y = atoi(b);
+
+    printf("%d",x>y ?  x : y);
+
+    return 0;
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/5622.c b/code_study/Baekjoon/c/5622.c
new file mode 100644
index 0000000..827a063
--- /dev/null
+++ b/code_study/Baekjoon/c/5622.c
@@ -0,0 +1,18 @@
+#include <stdio.h>
+
+int main(){
+    int dial[26] = {3,3,3,4,4,4,5,5,5,6,6,6,7,7,7,8,8,8,8,9,9,9,10,10,10,10};
+    char s[16];
+    int t=0;
+    
+    scanf("%s",s);
+
+    for(int i=0; s[i]!='\0'; i++){
+        t+=dial[(int)(s[i]-'A')];
+    }
+
+    printf("%d",t);
+
+    return 0;
+
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/9086.c b/code_study/Baekjoon/c/9086.c
new file mode 100644
index 0000000..573e8e7
--- /dev/null
+++ b/code_study/Baekjoon/c/9086.c
@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include <string.h>
+int main(){
+    int n;
+    char s[1001];
+    scanf("%d",&n);
+    while(n--){
+        scanf("%s",s);
+        printf("%c%c\n",s[0], s[strlen(s)-1]);
+    }
+    return 0;
+}
\ No newline at end of file