Function to check substring in a string

 int findstring(char *str,char *temp)

{

int i,j,len1,len2,valid=2;

len1=strlen(str);

len2=strlen(temp);

for(i=0;i<len1;i++)

{

valid=2;

if(str[i-1]==' ')

if(str[i]==temp[0])

for(j=0;j<len2;j++)

{

if(str[j+i]==temp[j])

{valid=1;}

else

{

valid=0;

break;

}

}

if(valid==1 && (str[i+len2]==' ' || str[i+len2]=='.'                    || str[i+len2]==',' || str[i+len2]=='\0'))

{

  

  return i;

   }

}

if(valid!=1)

{ 

  cout<<"\nstring not found ";

  return -1;

        }

}

function to insert a string temp into a              string str at index index

void insertstring(char *str,char *temp,int index)

{

   int j,i,len2,len1;

   len1=strlen(str);

   len2=strlen(temp);

   char temp2[100];

   strcpy(temp2,str+index);

   str[index]='\0';

   strcat(str+index,temp);

   str[index+len2]='\0';

   strcat(str," ");

   strcat(str,temp2);

}

Function to replace a substring(temp) of a string(str) with another substring(rep)

void replace(char *str,char *temp,char *rep)

{

 int index =findstring(str,temp);

int len2=strlen(temp);

char temp2[200];

strcpy(temp2,str+index+len2);

str[index]='\0';

strcat(str,rep);

strcat(str,temp2);

}

    Fuction to append a string 

VOID APPENDSTRING(char *str,char *strappend)

{

  strcat(str,strappend);

}