String functions in c language with examples | strcpy, strcat, strcmp, strrev, strlen in C

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 String functions in C language with examples | strcpy, strcat, strcmp, strrev, strlen in C

We need to include string.h header file in a program to use string functions. Different string functions in c language are:

1. strcpy() function in C Language

strcpy() is one of the most popular String functions in c language . This function is used store a value in a string variable 

Syntax :

strcpy(Str2,Str1);

Str2  is the string variable to store the value.

Str1 is the string value to be stored in string variable Str2.

We can’t use assignment operator = to assign a value to string variable. So we need to use strcpy() function to do that.

char name[20];
strcpy(name,”Amit”);

Program to demonstrate the use of strcpy() function in C.
#include<stdio.h>
#include<string.h>
int main()
{
char name[20];
strcpy(name,”Rahul”);
printf("name=%s",name);
return(0);
}
Output
name=Rahul

2. strcat() function in C Language

strcat() function is used to combine values of two string variables .

Syntax 

strcat(Str2,Str1);

Str2  is the string variable whose value will be combined with another string value.

Str1 is the string value to be combined with string variable Str2.

Program to demonstrate the use of strcat() function in C.
#include<stdio.h>
#include<string.h>
int main()
{
char name[30]=”Rahul”;
strcat(name,” Singh”);
printf("name=%s",name);
return(0);
}
Output
name=RahulSingh

Description of above program

In above program, string variable studentname contains value “Amit”. After applying strcat() function, its value will be concatenated with “ Singh” and the final value of string variable studentname would become Amit Singh.

3. strlen() function in C Language

strlen() function is used to count and return number of characters in a string value. 

Syntax :

strlen(Str);

Str is the string value whose length we want to find.

Program to demonstrate the use of strlen() function in C.

#include<stdio.h>
#include<string.h>
int main()
{
char name[30]="Rahul";
int num;
num=strlen(name);
printf("\nNumber of characters=%d",num);
return(0);
}
Output
Number of characters=5

Description of above program
In above program, string variable studentname contains value “Amit”. strlen() function finds number of characters in the value “Amit” in string variable studentname that  contains 4 characters. So strlen() would return 4.

 4. strrev() function in C Language

strrev() function is used to reverse the characters stored in a string value.

Syntax

strrev(Str);

Str is the string variable whose value we want to reverse.

Program to demonstrate the use of strrev() function in C.

#include<stdio.h>
#include<string.h>
int main()
{
char name[20]=”Rahul”;
strrev(name);
printf("name=%s",name);
return(0);
}
Output
name=luhaR

Description of above program

In above program, string variable name contains “Rahul”. strrev() reverses the value of name to make it luhaR.

5. strcmp() function in C Language

strcmp()  function is used to compare two string values. 0 is returned  if the values of strings being compared are same.

Syntax:

strcmp(Str1,Str2);

Here, Str1 and Str2 are string variables or constants which we want to compare.

Program to demonstrate the use of strcmp() function in C.

#include<stdio.h>
#include<string.h>
int main()
{
char name[35];
strcpy(name,”Sumit”);
if(strcmp(studentname,”Amit”)==0)
  cout<<”\nWelcome Amit”;
else
  cout<<”Wrong User”;
return(0);
}
Output
Wrong User

Description of above program

In this program, string variable name contains “Sumit”. String variable name has been compared with the string value Amit. Value of name i.e. sumit doesn’t match Amit so the output would be wrong user.

6. strcmpi() function in C Language

strcmpi()  function is used to compare string values but capital letters and small letters are considered same. 0 is returned  if the values of strings being compared are same.

Syntax:

strcmpi(Str1,Str2);

Here, Str1 and Str2 are string variables or constants which we want to compare.

Program to demonstrate the use of strcmpi() function in C 

#include<stdio.h>
#include<string.h>
int main()
{
char n1[30],n2[30];
printf("Enter a string value=");
gets(n1);
printf("Enter another string value=");
gets(2);
if(strcmpi(n1,n2)==0)
printf("Same");
else
printf("Not same");
return(0);
}
Output
Enter a string value=Aman
Enter another string value=AMAN
Same

Description of above program

In this program, string variable n1 contains value “Aman” and n2  contains “AMAN”. n1 and n2 contain same values with different cases. They are considered same so message “Same”  gets displayed .

7. strlwr() function in C Language

strlwr() function converts the uppercase letters to lowercase letters in a string value.

Syntax:

strlwr(Str);

Str is the string variable whose value we want to convert into lower case.

Program to demonstrate the use of strlwr() function in C

#include<stdio.h>
#include<string.h>
int main()
{
char sname[30]=”SUMIT”;
strlwr(sname);
printf("\nsname=%s",sname);
return(0);
}
Output
sname=sumit

Description of above program

In this program, string variable sname contains “Sumit”.  strlwr() function converts the value into small case i.e. sumit.

8. strupr() function in C Language

strupr() function converts the small case letters to capital letters in a string value.

strupr(Str);

Str is the string variable whose value we want to convert into capital letters.

Program to demonstrate the use of strupr() function in C

#include<stdio.h>
#include<string.h>
int main()
{
char sname[30]=”sumit”;
strupr(sname);
printf(“\nsname=%s”,sname);
return(0);
}
Output
sname=SUMIT

Description of above program

In this program, string variable sname contains “sumit”. strupr() function converts the value into capital case i.e. “SUMIT”.

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Lesson tags: assigning a value to string value in c, reversing a string value in c, strcat() function in C Language, strcpy() function of c, string comparison in C, string functions in c
Back to: C Programming Language
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