Language: C

int main(void){
    char W[10], T[1000];
    int n, k, l;
    size_t L;
    
    scanf("%s %s",W, T);
    printf("%s\nEND_OF_TEXT\n",T);
    L = strlen(W);
    
    for(k=0;k<1000;k++){
        if(strcmp(W[0],T[k])==0){
            for(l=0;l<L;l++){
                if(strcmp(T[k+l],W[l])!=0){break;}
                if(l==L-1){n++;}
            }
        }
    }
    printf("%d\n",n);
    
    return 0;
    
}

Compiler output:
main.c: In function 'main':
main.c:4:5: error: unknown type name 'size_t'
    4 |     size_t L;
      |     ^~~~~~
main.c:1:1: note: 'size_t' is defined in header '<stddef.h>'; this is probably fixable by adding '#include <stddef.h>'
  +++ |+#include <stddef.h>
    1 | int main(void){
main.c:6:5: error: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
    6 |     scanf("%s %s",W, T);
      |     ^~~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
  +++ |+#include <stdio.h>
    1 | int main(void){
main.c:6:5: warning: incompatible implicit declaration of built-in function 'scanf' [-Wbuiltin-declaration-mismatch]
    6 |     scanf("%s %s",W, T);
      |     ^~~~~
main.c:6:5: note: include '<stdio.h>' or provide a declaration of 'scanf'
main.c:7:5: error: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
    7 |     printf("%s\nEND_OF_TEXT\n",T);
      |     ^~~~~~
main.c:7:5: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:7:5: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
main.c:7:5: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:8:9: error: implicit declaration of function 'strlen' [-Wimplicit-function-declaration]
    8 |     L = strlen(W);
      |         ^~~~~~
main.c:1:1: note: include '<string.h>' or provide a declaration of 'strlen'
  +++ |+#include <string.h>
    1 | int main(void){
main.c:8:9: warning: incompatible implicit declaration of built-in function 'strlen' [-Wbuiltin-declaration-mismatch]
    8 |     L = strlen(W);
      |         ^~~~~~
main.c:8:9: note: include '<string.h>' or provide a declaration of 'strlen'
main.c:11:12: error: implicit declaration of function 'strcmp' [-Wimplicit-function-declaration]
   11 |         if(strcmp(W[0],T[k])==0){
      |            ^~~~~~
main.c:11:12: note: include '<string.h>' or provide a declaration of 'strcmp'
main.c:11:20: error: passing argument 1 of 'strcmp' makes pointer from integer without a cast [-Wint-conversion]
   11 |         if(strcmp(W[0],T[k])==0){
      |                   ~^~~
      |                    |
      |                    char
main.c:11:20: note: expected 'const char *' but argument is of type 'char'
main.c:11:25: error: passing argument 2 of 'strcmp' makes pointer from integer without a cast [-Wint-conversion]
   11 |         if(strcmp(W[0],T[k])==0){
      |                        ~^~~
      |                         |
      |                         char
main.c:11:25: note: expected 'const char *' but argument is of type 'char'
main.c:13:28: error: passing argument 1 of 'strcmp' makes pointer from integer without a cast [-Wint-conversion]
   13 |                 if(strcmp(T[k+l],W[l])!=0){break;}
      |                           ~^~~~~
      |                            |
      |                            char
main.c:13:28: note: expected 'const char *' but argument is of type 'char'
main.c:13:35: error: passing argument 2 of 'strcmp' makes pointer from integer without a cast [-Wint-conversion]
   13 |                 if(strcmp(T[k+l],W[l])!=0){break;}
      |                                  ~^~~
      |                                   |
      |                                   char
main.c:13:35: note: expected 'const char *' but argument is of type 'char'