C Programming String Functions

String Functions

• Library: ``
• Functions:
  • strlen(str): returns the length of the string
  • strcpy(dest, src): copies the string src to dest
  • strcat(dest, src): concatenates src to the end of dest
  • strcmp(str1, str2): compares two strings, returns 0 if equal
  • strchr(str, c): returns a pointer to the first occurrence of character c in str
  • strstr(str1, str2): returns a pointer to the first occurrence of str2 in str1

String Manipulation

• Functions:
  • strupr(str): converts a string to uppercase
  • strlwr(str): converts a string to lowercase
  • strupr(str): converts the first character of a string to uppercase
  • strrev(str): reverses a string
• Note: These functions are not part of the standard `` library, but are commonly used in string manipulation.

String Concatenation

• Using strcat():
  • strcat(str1, str2): concatenates str2 to the end of str1
  • Example: strcat("Hello, ", "World!") results in "Hello, World!"
• Using array indexing:
  • Example: char str[20]; strcpy(str, "Hello"); str[5] = ','; strcat(str, " World!"); results in "Hello, World!"
• Using sprintf():
  • sprintf(str, "format string", arguments): formats a string using the format string and arguments
  • Example: sprintf(str, "Hello, %s!", "World") results in "Hello, World!"

String Functions

• strlen(str) returns the length of the string.
• strcpy(dest, src) copies the string src to dest.
• strcat(dest, src) concatenates src to the end of dest.
• strcmp(str1, str2) compares two strings and returns 0 if they are equal.
• strchr(str, c) returns a pointer to the first occurrence of character c in str.
• strstr(str1, str2) returns a pointer to the first occurrence of str2 in str1.

String Manipulation

• strupr(str) converts a string to uppercase.
• strlwr(str) converts a string to lowercase.
• strupr(str) converts the first character of a string to uppercase.
• strrev(str) reverses a string.
• Note: These functions are not part of the standard library, but are commonly used in string manipulation.

String Concatenation

• strcat(str1, str2) concatenates str2 to the end of str1.
• Example: strcat("Hello, ", "World!") results in "Hello, World!".
• Concatenation using array indexing: Example: char str; strcpy(str, "Hello"); str[5] = ','; strcat(str, " World!"); results in "Hello, World!".
• sprintf(str, "format string", arguments) formats a string using the format string and arguments.
• Example: sprintf(str, "Hello, %s!", "World") results in "Hello, World!".