Lab program-2
Design, Develop and Implement a Program in C for the following operations on Strings
a. Read a main String (STR), a Pattern String (PAT) and a Replace String (REP)
b. Perform Pattern Matching Operation: Find and Replace all occurrences of PAT in STR with REP if PAT exists in STR. Report suitable messages in case PAT does not exist in STR.
Support the program with functions for each of the above operations. Don't use Built-in functions.
#include<stdio.h>
void main()
{
char STR[100],PAT[100],REP[100],ans[100];
int i,j,c,m,k,flag=0;
printf("\nEnter the MAIN string: \n");
gets(STR);
printf("\nEnter a PATTERN string: \n");
gets(PAT);
printf("\nEnter a REPLACE string: \n");
gets(REP);
i = m = c = j = 0;
while ( STR[c] != '\0')
{
// Checking for Match
if ( STR[m] == PAT[i] )
{
i++;
m++;
flag=1;
if ( PAT[i] == '\0')
{
//copy replace string in ans string
for(k=0; REP[k] != '\0';k++,j++)
ans[j] = REP[k];
i=0;
c=m;
}
}
else //mismatch
{
ans[j] = STR[c];
j++;
c++;
m = c;
i=0;
}
}
if(flag==0)
{
printf("Pattern doesn't found!!!");
}
else
{
ans[j] = '\0';
printf("\nThe RESULTANT string is:%s\n" ,ans);
}
}
//END OF PROGRAM
void main()
{
char STR[100],PAT[100],REP[100],ans[100];
int i,j,c,m,k,flag=0;
printf("\nEnter the MAIN string: \n");
gets(STR);
printf("\nEnter a PATTERN string: \n");
gets(PAT);
printf("\nEnter a REPLACE string: \n");
gets(REP);
i = m = c = j = 0;
while ( STR[c] != '\0')
{
// Checking for Match
if ( STR[m] == PAT[i] )
{
i++;
m++;
flag=1;
if ( PAT[i] == '\0')
{
//copy replace string in ans string
for(k=0; REP[k] != '\0';k++,j++)
ans[j] = REP[k];
i=0;
c=m;
}
}
else //mismatch
{
ans[j] = STR[c];
j++;
c++;
m = c;
i=0;
}
}
if(flag==0)
{
printf("Pattern doesn't found!!!");
}
else
{
ans[j] = '\0';
printf("\nThe RESULTANT string is:%s\n" ,ans);
}
}
//END OF PROGRAM
