This handout explains string concept in C programming language.

1. C-Programming
Walchand Institute of Technology (RC1131), Solapur Page 1
Handout#8
Assignment/Program Statement:
Write a C program using String – Find Number of Vowels, Consonants, Digits and
White Space Character
Learning Objectives:
Students will be able to
- declare and initialize and the string
- read and display the string
- write the program to manipulate the string
Theory:
 In C programming, array of character are called strings. A string is
terminated by null character /0. For example:
"c string tutorial"
Here, "c string tutorial" is a string. When, compiler encounters strings, it
appends null character at the end of string.
 Declaration of strings
Strings are declared in C in similar manner as arrays. Only difference is that,
strings are of char type.
char s[5];
Strings can also be declared using pointer.
char *p
 Initialization of strings
In C, string can be initialized in different number of ways.
char c[]="abcd";
OR,
char c[5]="abcd";
OR,

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char c[]={'a','b','c','d','0'};
OR;
char c[5]={'a','b','c','d','0'};
String can also be initialized using pointers
char *c="abcd";
 Reading Strings from user
o Reading words from user.
char c[20];
scanf("%s",c);
String variable c can only take a word. It is beacause when white
space is encountered, the scanf() function terminates.
Write a C program to illustrate how to read string from terminal.
#include <stdio.h>
int main(){
char name[20];
printf("Enter name: ");
scanf("%s",name);
printf("Your name is %s.",name);
return 0;
}
Output
Enter name: Dennis Ritchie
Your name is Dennis.
Here, program will ignore Ritchie because, scanf() function takes
only string before the white space.
o Reading a line of text
C program to read line of text manually.
#include <stdio.h>
int main(){

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char name[30],ch;
int i=0;
printf("Enter name: ");
while(ch!='n') // terminates if user hit enter
{
ch=getchar();
name[i]=ch;
i++;
}
name[i]='0'; // inserting null character at end
printf("Name: %s",name);
return 0;
}
This process to take string is tedious. There are predefined functions
gets() and puts in C language to read and display string respectively.
int main(){
char name[30];
printf("Enter name: ");
gets(name); //Function to read string from user.
printf("Name: ");
puts(name); //Function to display string.
return 0;
}
Both, the above program has same output below:
Output
Enter name: Tom Hanks
Name: Tom Hanks
 C supports a wide range of functions that manipulate null-terminated strings

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So.No. Function & Purpose
1 strcpy(s1, s2);
Copies string s2 into string s1.
2 strcat(s1, s2);
Concatenates string s2 onto the end of string s1.
3 strlen(s1);
Returns the length of string s1.
4 strcmp(s1, s2);
Returns 0 if s1 and s2 are the same; less than 0 if s1<s2; greater
than 0 if s1>s2.
5 strchr(s1, ch);
Returns a pointer to the first occurrence of character ch in string
s1.
6 strstr(s1, s2);
Returns a pointer to the first occurrence of string s2 in string s1.
 gets() and puts()
Functions gets() and puts() are two string functions to take string input from
user and display string respectively as mentioned in previous chapter.
#include<stdio.h>
int main(){
char name[30];
printf("Enter name: ");
gets(name); //Function to read string from user.
printf("Name: ");
puts(name); //Function to display string.
return 0;
}

5. C-Programming
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Though, gets() and puts() function handle string, both these functions are
defined in "stdio.h" header file
[Reference: http://www.tutorialspoint.com/cprogramming/c_strings.htm and
http://www.programiz.com/c-programming/string-handling-functions ]

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Flowchart for Problem Statement:

7. C-Programming
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Algorithm:
1. Start
2. v=c=d=s=0
3. read the line of string
4. if line[i]!=’0’
if (line[i]=='a' || line[i]=='e' || line[i]=='i' || line[i]=='o' || line[i]=='u' ||
line[i]=='A' || line[i]=='E' || line[i]=='I' || line[i]=='O' || line[i]=='U')
c++
go to step 4
elseif ((line[i]>='a'&& line[i]<='z') || (line[i]>='A'&& line[i]<='Z'))
v++
go to step 4
elseif(line[i]>='0'&&c<='9')
d++
go to step 4
elseif (line[i]==' ')
s++
go to step 4
else
go to step 5
5. Display Vowels, Consonants, Digits and White spaces
6. Stop
Program:
#include<stdio.h>
int main()
{
char line[150];
int i,v,c,ch,d,s,o;
v=c=d=s=0;
printf("Enter a line of string:n");
gets(line);
for(i=0;line[i]!='0';++i)
{

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if(line[i]=='a' || line[i]=='e' || line[i]=='i' || line[i]=='o' || line[i]=='u' ||
line[i]=='A' || line[i]=='E' || line[i]=='I' || line[i]=='O' || line[i]=='U')
++v;
else if((line[i]>='a'&& line[i]<='z') || (line[i]>='A'&& line[i]<='Z'))
++c;
else if(line[i]>='0'&&c<='9')
++d;
else if (line[i]==' ')
++s;
}
printf("Vowels: %d",v);
printf("nConsonants: %d",c);
printf("nDigits: %d",d);
printf("nWhite spaces: %d",s);
return 0;
}
Input:
Enter a line of string:
This program is easy 2 understand
Output:
Vowels: 9
Consonants: 18
Digits: 1
White spaces: 5
Practice Problem Statement:
1. Write a C program to find the Length of a String.
2. Write a C program to Concatenate Two Strings.
3. Write a C program to Copy a String.
4. Write a C program to remove all characters in a String except alphabet.

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Conclusion:
Thus a C program using string – Find Number of Vowels, Consonants, Digits and
White Space Character is implemented.
Learning Outcomes:
At the end of this assignment, students are able to
- declare and initialize and the string
- read and display the string
- write the program to manipulate the string