Insert | Delete | Replace

    

#include<stdio.h>
#include<string.h>
#include<stdlib.h> // for exit using in the switch's default case

int len(char str[]){
int i=0;
while(str[i]!='\0'){
i++;
}
return i ;
}
void insert(char string[50]){
int pos;
printf("Enter the position: \n");
scanf("%d",&pos);
getchar();// flushes newline from buffer since we are using fgets after a scanf

char ins[25];
printf("Enter the string to be inserted: \n");
fgets(ins,25,stdin);
ins[strcspn(ins,"\n")]='\0';

char firstString[50];
int j=0;
for(j=0;string[j]!=string[pos-1];j++){
firstString[j]=string[j];
}
firstString[j]='\0';
printf("\n first string: %s\n",firstString);

strcat(firstString,ins);

char secondString[50];
int k=0;
for(int i=pos-1;string[i]!='\0';i++){
printf("%c \n",string[i]);
secondString[k]=string[i];
k++;
}
secondString[k]='\0';// terminating the string so no garbage is given place

strcat(firstString,secondString);

printf("Final string: %s",firstString);

}

void delete(char string[]){
int pos,n;
printf("Enter the position to delete from: \n");
scanf("%d",&pos);

printf("Enter the length to delete: \n");
scanf("%d",&n);
char firstString[50];
int j=0;
for(j=0;j!=pos-1;j++){
firstString[j]=string[j];
}
firstString[j]='\0';

char secondString[50];
int k=0;
for(int i=pos+n-1;string[i]!='\0';i++){
secondString[k]=string[i];
k++;
}
secondString[k]='\0';// temrination
strcat(firstString,secondString);
printf("\n Final string: %s",firstString);
}


int getpos(char dpat[],char string[]){
int j,k,i=0;
while(string[i]!='\0'){
if(string[i]==dpat[0]){
j=1;
while(dpat[j]!='\0' && string[j+i]!='\0' && string[j+i]==dpat[j]){
j++;
k=1;
}
if(dpat[j]=='\0'){
printf("\n Pattern string %s found at position %d : ",dpat,i+1);
return i+1;
}
}
i++;
}
if(k==0){
printf("\n Given pattern not found! \n");
return -1;
}

}



void replace(char string[]){
char dpat[50],ipat[50];
// take pattern to delete
printf("Enter the string part you want to delete: \n");
getchar();
fgets(dpat,50,stdin);
dpat[strcspn(dpat,"\n")]='\0';

// take pattern to insert
printf("Enter the string that you want to insert in its place: \n");
fgets(ipat,50,stdin);
ipat[strcspn(ipat,"\n")]='\0';

int pos=getpos(dpat,string);
int l;
if(pos!=-1){
l=len(dpat);
// Impleting deletion operation
char firstString[50];
int j=0;
for(j=0;j!=pos-1;j++){
firstString[j]=string[j];
}
firstString[j]='\0';

char secondString[50];
int k=0;
for(int i=pos+l-1;string[i]!='\0';i++){
secondString[k]=string[i];
k++;
}
secondString[k]='\0';// temrination
strcat(firstString,secondString);
strcpy(string,firstString);
// implementing the insertion operationg
char ifirstString[50];
int ij=0;
for(ij=0;string[ij]!=string[pos-1];ij++){
ifirstString[ij]=string[ij];
}
ifirstString[ij]='\0';
printf("\n first string: %s\n",ifirstString);

strcat(ifirstString,ipat);

char isecondString[50];
int ik=0;
for(int i=pos-1;string[i]!='\0';i++){
printf("%c \n",string[i]);
isecondString[ik]=string[i];
ik++;
}
isecondString[ik]='\0';// terminating the string so no garbage is given place

strcat(ifirstString,isecondString);
strcpy(string,ifirstString);

printf("\n\n**Final string: %s \n\n",string);


}


}
int main(){

char string[50];
printf("Enter the string: \n");
fgets(string,50,stdin);
string[strcspn(string,"\n")]='\0';

int ch;
while(1){
printf("\n1.Insert\t 2.Delete\t 3.Replace\n");
scanf("%d",&ch);
switch(ch){
case 1:insert(string);
break;
case 2:delete(string);//deleted a length from specified position
break;
case 3:replace(string);
break;
default:exit(0);
}
}
return 0;
}