C

c strcat

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

int main() {
  /*
  strcat(char * destination, const char *source)
  attaches source to destination
  */
  
  char buffer[100] = "Hello ";
  strcat(buffer, "World!");
  printf("Buffer: %s
", buffer);
  return 0;
}

c strstr

// CPP program to illustrate strstr()
#include <string.h>
#include <stdio.h>
  
int main()
{
    // Take any two strings
    char s1[] = "GeeksforGeeks";
    char s2[] = "for";
    char* p;
  
    // Find first occurrence of s2 in s1
    p = strstr(s1, s2);
  
    // Prints the result
    if (p) {
        printf("String found
");
        printf("First occurrence of string '%s' in '%s' is '%s'", s2, s1, p);
    } else
        printf("String not found
");
  
    return 0;
}