C strcat

The strcat() function takes two arguments:

destination - destination string
source - source string

The strcat() function concatenates the destination string and the source string, and the result is stored in the destination string.

 Example 

#include <stdio.h>
#include <string.h>
int main() {
   char str1[100] = "This is ", str2[] = "mybcaclassnotes.blogspot.com";

   // concatenates str1 and str2
   // the resultant string is stored in str1.
   strcat(str1, str2);

   puts(str1);
   puts(str2);

   return 0;
}

Output:

 

 

Concatenate Two Strings Without Using strcat()

 

 #include <stdio.h>
int main() {
  char s1[100] = "programming ", s2[] = "is awesome";
  int length, j;

  // store length of s1 in the length variable
  length = 0;
  while (s1[length] != '\0') {
    ++length;
  }

  // concatenate s2 to s1
  for (j = 0; s2[j] != '\0'; ++j, ++length) {
    s1[length] = s2[j];
  }

  // terminating the s1 string
  s1[length] = '\0';

  printf("After concatenation: ");
  puts(s1);

  return 0;
}

or

#include<stdio.h>

#include<conio.h>

int main()

{

  char str1[25],str2[25];

  int i=0,j=0;

  printf("\nEnter First String:");

  gets(str1);

  printf("\nEnter Second String:");

  gets(str2);

  while(str1[i]!='\0')

  i++;

  while(str2[j]!='\0')

  {

    str1[i]=str2[j];

    j++;

    i++;

  }

  str1[i]='\0';

  printf("\nConcatenated String is %s",str1);

  getch();

  return 0;

}

 Output