A1802200285_23838_11_2018_string-programs.doc

1. String length C program #include <stdio.h> #include <string.h> int main() { char a[100]; int length; printf("Enter a string to calculate it's length\n"); gets(a); length = strlen(a); printf("Length of the string = %d\n", length); return 0; }

String length in C without strlen

You can also find string length without strlen function. We create our function to find it. We scan all the characters in the string if the character isn't a null character then increment the counter by one. Once the null character is found the counter equals length of the string. #include <stdio.h> int main() { char s[1000]; int c = 0; printf("Input a string\n"); gets(s); while (s[c] != '\0') c++; printf("Length of the string: %d\n", c); return 0; }

2. String comparison

#include <stdio.h> #include <string.h> int main() { char a[100], b[100]; printf("Enter a string\n"); gets(a); printf("Enter a string\n"); gets(b); if (strcmp(a,b) == 0) printf("The strings are equal.\n"); else printf("The strings are not equal.\n"); }

return 0;

C string comparison program without strcmp We can create a function to compare two strings. #include <stdio.h> int compare_strings(char [], char []); int main() { char a[1000], b[1000]; printf("Input a string\n"); gets(a); printf("Input a string\n"); gets(b); if (compare_strings(a, b) == 0) printf("Equal strings.\n"); else printf("Unequal strings.\n"); return 0; } int compare_strings(char a[], char b[])

{

int c = 0; while (a[c] == b[c]) { if (a[c] == '\0' || b[c] == '\0') break; c++; }

}

if (a[c] == '\0' && b[c] == '\0') return 0; else return -1;

3. String copy C program

#include <stdio.h> #include <string.h>

int main() { char source[1000], destination[1000]; printf("Input a string\n"); gets(source); strcpy(destination, source); printf("Source string: %s\n", source); printf("Destination string: %s\n", destination); return 0; }

Copy string in C without using strcpy #include <stdio.h>

int main() { int c = 0; char s[1000], d[1000] = "What can I say about my programming skills?"; printf("Before copying, the string: %s\n", d); printf("Input a string to copy\n"); gets(s);

while (s[c] != '\0') { d[c] = s[c]; c++; } d[c] = '\0'; printf("After copying, the string: %s\n", d); }

return 0;

C program to concatenate strings #include <stdio.h> #include <string.h> int main() { char a[1000], b[1000]; printf("Enter the first string\n"); gets(a); printf("Enter the second string\n"); gets(b); strcat(a, b); printf("String obtained on concatenation: %s\n", a); return 0; }

Concatenate strings without strcat function

C program to concatenate strings without using library function strcat of string.h header file. We create our own function. #include <stdio.h> void concatenate(char [], char []); int main() { char p[100], q[100]; printf("Input a string\n");

gets(p); printf("Input a string to concatenate\n"); gets(q); concatenate(p, q); printf("String obtained on concatenation: \"%s\"\n", p); return 0; } void concatenate(char p[], char q[]) { int c, d; c = 0; while (p[c] != '\0') { c++; } d = 0; while (q[d] != '\0') { p[c] = q[d]; d++; c++; } p[c] = '\0'; }

4. Reverse a string in C using strrev

#include <stdio.h> #include <string.h> int main() { char arr[100];

printf("Enter a string to reverse\n"); gets(arr); strrev(arr); printf("Reverse of the string is \n%s\n", arr);

}

return 0;

String reversal without strrev function

First we calculate length of the string without using strlen function and then copy its characters in reverse order (from end to beginning) to a new string using a for loop. #include <stdio.h> int main() { char s[1000], r[1000]; int begin, end, count = 0; printf("Input a string\n"); gets(s); // Calculating string length while (s[count] != '\0') count++; end = count - 1; for (begin = 0; begin < count; begin++) { r[begin] = s[end]; end--; } r[begin] = '\0'; printf("%s\n", r); return 0; }

C program remove spaces, blanks from a string #include <stdio.h> int main() { char text[1000], blank[1000]; int c = 0, d = 0; printf("Enter some text\n"); gets(text);

while (text[c] != '\0') { if (text[c] == ' ') { int temp = c + 1; if (text[temp] != '\0') { while (text[temp] == ' ' && text[temp] != '\0') { if (text[temp] == ' ') { c++; } temp++; } } } blank[d] = text[c]; c++; d++; } blank[d] = '\0'; printf("Text after removing blanks\n%s\n", blank); }

return 0;